Math Tools

Convert CTC to take-home salary with PF, ESI, professional tax, and income tax deductions. Compare old vs new tax regime. FY 2024-25. Free online salary breakup calculator India — no signup required.

Calculate your financial independence number from annual expenses and safe withdrawal rate. See years to FIRE, Lean/Regular/Fat FIRE variants, and year-by-year portfolio projection. Free online FIRE calculator — no signup required.

Calculate net present value from discount rate and cash flow series. See present value of each period, cumulative NPV, payback period, and accept/reject recommendation. Free online NPV calculator — no signup required.

Calculate fixed deposit maturity amount, total interest earned, and effective annual rate with quarterly, monthly, or annual compounding. Year-by-year growth table included. Free online FD calculator — no signup required.

Calculate monthly car loan EMI, total interest, and total cost of ownership from vehicle price, down payment, interest rate, and tenure. Full amortization schedule included. Free online car loan calculator — no signup required.

Calculate compound interest with annual, quarterly, monthly, or daily compounding. See total amount, total interest, effective annual rate, and a year-by-year growth table. Free online compound interest calculator — no signup required.

Calculate maturity amount, wealth gained, CAGR, and inflation-adjusted real value for any one-time lumpsum investment. Year-by-year growth table included. Free online lumpsum investment calculator.

Calculate National Savings Certificate maturity amount, total interest, and Section 80C tax benefit for any investment. Current NSC rate 7.7% p.a., 5-year tenure, year-by-year accrual schedule. Free online NSC calculator.

Calculate SIP maturity value, wealth gained, and year-by-year growth for any monthly investment, return rate, and duration. Includes rate comparison table — free online SIP calculator, no signup required.

Calculate compound annual growth rate from beginning and ending values, compute future value from CAGR, or find investment duration. Year-by-year breakdown — free online CAGR calculator, no signup required.

Calculate inflation-adjusted real return using the Fisher equation. Compare nominal vs real return, see purchasing power erosion year by year — free online real return calculator, no signup required.

Calculate House Rent Allowance exemption under Section 10(13A) of the Income Tax Act. Shows all three conditions with metro/non-metro support — free online HRA exemption calculator, no signup required.

Calculate total return, percentage gain/loss, and annualized return (CAGR) for any stock investment. Includes dividends, brokerage fees, and break-even price. Free online stock return calculator.

Calculate final portfolio value, absolute returns, and XIRR for ELSS and equity mutual fund investments. Supports lumpsum and SIP modes with CAGR comparison table and year-by-year growth — free online ELSS mutual fund returns calculator, no signup required.

Calculate inflation-adjusted value, purchasing power loss, and year-by-year breakdown for any amount, year range, and inflation rate. Works for past and future values — free online inflation calculator, no signup required.

Calculate simple interest using the SI = P × R × T formula. Supports annual, monthly, and daily rate inputs with years, months, or days as the time unit. See total amount, accrual rates, and time period comparison. Free online simple interest calculator — no signup required.

Three modes: What is X% of Y? X is what % of Y? X is Y% of what? The most-searched basic math query globally. Free online percentage calculator — no signup required.

Solve A/B = C/D — enter three known values and instantly find the fourth using cross-multiplication. Handles percentage-of-whole problems too. Free online proportion calculator — no signup required.

Simplify a ratio to its lowest terms using GCD, scale a ratio by any factor, or find the missing value in a proportion a : b = c : ? using cross-multiplication. Shows decimal equivalent, percentage, and visual proportion bar. Free online ratio calculator — no signup required.

Calculate the mean, median, mode, range, geometric mean, and harmonic mean for any list of numbers. Supports comma, space, or newline separated lists. Free online average calculator — no signup required.

Compute the weighted mean of up to 20 value-weight pairs with optional labels. Shows contribution breakdown, visual bars, and simple average comparison. Free online weighted average calculator — no signup required.

Input probability-value pairs to compute E[X], variance, standard deviation, skewness, kurtosis, and a full probability distribution table. Free online expected value calculator — no signup required.

Calculate mean, median, mode, range, variance, standard deviation, quartiles (Q1/Q2/Q3), IQR, skewness, kurtosis, SEM, and coefficient of variation from any list of numbers. Includes Tukey outlier detection, frequency table, and distribution chart. Free online statistics calculator — no signup required.

Convert a Z-score or t-statistic to two-tailed, left-tailed, and right-tailed p-values. Supports Z-tests (normal distribution) and t-tests (Student t-distribution with any degrees of freedom). Includes significance table at α = 0.001, 0.01, 0.05, 0.10 and plain-English interpretation. Free online p-value calculator — no signup required.

Calculate Pearson r, R² (coefficient of determination), t-statistic, p-value, and linear regression equation from two data series. Includes scatter plot with regression line and correlation strength interpretation. Free online correlation coefficient calculator — no signup required.

Calculate population standard deviation (σ) and sample standard deviation (s) from any dataset. Includes variance (population & sample), mean, median, coefficient of variation, step-by-step deviation table, and a built-in Z-score calculator with percentile rank. Free online standard deviation calculator — no signup required.

One-way ANOVA from group data — compute F-statistic, exact p-value, sum of squares table (SS, df, MS), effect sizes (η², ω²), and group descriptive statistics. Handles unequal group sizes. Free online ANOVA calculator — no signup required.

Convert between standard, scientific, engineering, and e-notation instantly. See SI prefix and approximate words. Free online scientific notation converter — no signup required.

Raise any base to a positive, negative, or decimal power instantly. Supports exact BigInt precision digits and scales the prime factorization of results. Free online exponent calculator — no signup required.

Round numbers to custom decimal places, significant figures, nearest integer, nearest 0.5, or nearest power of 10. Supports visual rounding steps and multiple modes like round up, round down, ceiling, and floor. Free online rounding calculator.

Compute logarithms for any base (base 10, natural log base e, binary log base 2, or custom base) and calculate antilogarithms instantly. Provides detailed step-by-step mathematical explanations and parameters validation. Free online logarithm calculator.

Solve any triangle from SSS, SAS, ASA, AAS, or SSA inputs. Computes all sides, angles, area, perimeter, inradius, and circumradius. Handles the SSA ambiguous case. Free online triangle calculator — no signup required.

Run one-sample, two-sample (Welch's), and paired t-tests. Get t-statistic, degrees of freedom, exact p-value, Cohen's d effect size, 95% CI, and step-by-step solution. Free online t-test calculator — no signup required.

Compute P(X=k), P(X≤k), P(X≥k) for any B(n,p) distribution with bar chart visualization, mean, variance, and PMF formula. Supports n up to 1,000. Free online binomial distribution calculator — no signup required.

Add, subtract, multiply matrices; compute transpose, determinant, inverse (Gauss-Jordan), and RREF for 2×2, 3×3, and 4×4 matrices. Free online matrix calculator — no signup required.

Solve any quadratic equation ax²+bx+c=0 instantly. Get real and complex roots, discriminant analysis, vertex, axis of symmetry, parabola graph, and step-by-step solution. Free online quadratic equation solver — no signup required.

Solve any cubic equation ax³+bx²+cx+d=0 analytically with Cardano's method. Get all three roots (real or complex), discriminant, depressed cubic, Vieta's formulas, and step-by-step solution. Free online cubic equation solver — no signup required.

Convert paper sizes to mm, cm, and inches — A0–A10, B0–B10, C0–C10, US Letter, Legal, Tabloid, and ANSI sizes. Includes diagonal calculation and full series comparison table. Free online paper size converter — no signup required.

Convert women's tops, bottoms, dresses, and children's clothing sizes between US, UK, EU, IT (Italy), and FR (France) systems. Includes body measurement references for each size. Free online clothing size converter — no signup required.

Convert density units between kg/m³, g/cm³, g/mL, g/L, lb/ft³, lb/in³, lb/gal, slug/ft³, t/m³ and more. Includes a material reference table for water, steel, gold, and concrete. Free online density converter — no signup required.

Convert data storage units between bits, bytes, KB, MB, GB, TB, PB, EB, and all IEC binary units (KiB, MiB, GiB, TiB, PiB). Supports decimal (SI) and binary (IEC) standards with a full conversion table. Free online data storage converter — no signup required.

Convert area units instantly between mm², cm², m², km², in², ft², yd², mi², acres, and hectares. Supports metric, imperial, and agricultural units with a full conversion table. Free online area converter — no signup required.

Convert between 23 volume units — metric (mL, L, m³, cm³), US customary (fl oz, cup, pint, quart, gallon, barrel), UK imperial (fl oz, pint, quart, gallon), and cooking measures (tsp, tbsp). Full conversion table. Free online volume converter — no signup required.

Convert between 20 energy units — SI/metric (J, kJ, MJ, GJ), thermal (cal, kcal, BTU, therm), electrical (Wh, kWh, MWh), mechanical (ft·lbf, erg), and atomic (eV, keV, MeV, Hartree). Full conversion table. Free online energy converter — no signup required.

Convert between 14 angle units — degrees, radians, gradians, turns, arcminutes, arcseconds, milliradians, angular mils, and more. DMS display and full conversion table. Free online angle converter — no signup required.

Convert cups, tablespoons, teaspoons, mL, fl oz, and grams for 30+ common ingredients. Volume-to-volume, volume-to-grams, and grams-to-volume modes. Free online cooking measurement converter — no signup required.

Look up past exchange rates for any date from 1999-01-04 to yesterday. ECB reference rates for 32 currencies via Frankfurter API. Free online historical currency converter — no signup required.

Simplify any fraction to its lowest terms with step-by-step GCD breakdown, mixed number conversion, decimal and percentage equivalents. Free online fraction simplifier — no signup required.

Convert any decimal to an exact fraction including repeating decimals. Parentheses notation for repeating blocks, step-by-step breakdown, mixed number form. Free online decimal to fraction converter — no signup required.

Convert between Celsius, Fahrenheit, Kelvin, and Rankine instantly. See the exact conversion formula, an all-scales result table, and quick reference temperatures. Free online temperature converter — no signup required.

Convert between N·m, ft·lbf, in·lbf, kgf·m, kgf·cm, ozf·in, dyn·cm, and 8 more torque units instantly. Full conversion table and quick reference values included. Free online torque converter — no signup required.

Convert between US Men, US Women, UK, EU, Japan, and foot length in cm and inches. Full shoe size chart with all systems side by side. Free online shoe size converter — no signup required.

Convert between Hindu-Arabic, Roman, Chinese, Egyptian hieroglyphic, and Babylonian cuneiform numerals. See all five systems at once with range validation. Free online numeral system converter — no signup required.

Add, subtract, multiply, and divide fractions and mixed numbers. See step-by-step solutions, simplified results, and decimal equivalents. Free online fraction calculator — no signup required.

Calculate the Least Common Multiple of up to 20 integers with prime factorisation steps and divisibility verification. Free online LCM calculator — no signup required.

Compute P(n,r) and C(n,r) with formula display, step-by-step solutions, Pascal's Triangle row, and BigInt support up to n=1000. Free online permutation combination calculator — no signup required.

Solve 2×2 and 3×3 systems of linear equations using Gaussian elimination with step-by-step matrix operations and solution verification. Free online linear equations solver — no signup required.

Calculate P(X < x), P(X > x), and P(a < X < b) for any normal distribution with bell curve visualization, z-score, and PDF value. Free online normal distribution calculator — no signup required.

Calculate χ², degrees of freedom, and p-value for goodness-of-fit and independence tests. Supports contingency tables up to 5×5 with cell-by-cell breakdown. Free online chi-square calculator — no signup required.

Solve for any missing side of a right-angled triangle (side a, side b, or hypotenuse c) instantly. Displays step-by-step formula substitutions and scans for nearby integer Pythagorean triples. Free online Pythagorean calculator — no signup required.

Calculate the Greatest Common Divisor of 2–10 integers with step-by-step Euclidean algorithm, prime factorizations, and all divisors of the GCD. Free online GCD calculator — no signup required.

Compute N! exactly for N = 0 to 1000 using BigInt arithmetic. Shows scientific notation, digit count, trailing zeros (Legendre's formula), Stirling's approximation, and the full exact value. Free online factorial calculator — no signup required.

Solve ax + b = c for x with step-by-step algebraic solution, fraction form, and verification. Handles unique, no solution, and infinite solution cases. Free online linear equation solver — no signup required.

Calculate slope, angle of inclination, y-intercept, and line equation from two points. Shows step-by-step solution with distance and midpoint. Handles vertical and horizontal lines. Free online slope calculator — no signup required.

Interactive unit circle showing exact sin, cos, and tan values for all 16 standard angles. Click any point to see exact fraction and radical values, decimal approximations, radian equivalents, and all 6 trig functions. Free online unit circle reference — no signup required.

Calculate Euclidean distance, Manhattan distance, Chebyshev distance, and midpoint between two (x, y) points. Shows step-by-step solution with Δx and Δy breakdown. Free online coordinate distance calculator — no signup required.

Compute confidence interval bounds from sample mean, SD, and n using t-distribution or z-distribution. Shows step-by-step calculation, margin of error, and visual CI bar. Free online confidence interval calculator — no signup required.

Compute z-score, percentile rank, P(X < x), P(X > x), and two-tailed probability from value, mean, and SD. Bell curve visualization included. Free online z-score calculator — no signup required.

Calculate % increase or decrease between two values, find new value after % change, or find original value before % change. Shows step-by-step calculation. Free online percentage change calculator — no signup required.

Decompose any integer into its prime factors with step-by-step trial division, all divisors, divisor count, divisor sum, and perfect number detection. Supports numbers up to 1 trillion. Free online prime factorization tool — no signup required.

Find all factors (divisors) of any integer up to 1 trillion instantly. Shows prime factorization with exponents, divisor count, divisor sum, and classifies the number as prime, perfect, abundant, or deficient. Free online factor finder — no signup required.

Calculate the area and perimeter of two-dimensional geometric shapes (square, rectangle, circle, triangle, trapezoid, parallelogram, ellipse, sector, regular polygon) instantly with step-by-step formulas. Free online area calculator.

Calculate the perimeter and circumference of two-dimensional shapes (square, rectangle, circle, triangle, trapezoid, parallelogram, ellipse, sector, regular polygon) instantly. Features Ramanujan ellipse approximations and step-by-step formulas. Free online perimeter calculator.

Calculate circle properties (radius, diameter, circumference, and area) instantly. Enter any one property to solve for all others with detailed step-by-step formula calculations. Free online circle calculator.

Calculate the surface area of three-dimensional geometric shapes (cube, cuboid, sphere, cylinder, cone, frustum, torus) instantly. Features detailed formula displays and parameter checks. Free online surface area calculator.

Calculate the volume and total surface area of three-dimensional geometric shapes (cube, cuboid, sphere, cylinder, cone, square pyramid, torus, hemisphere, ellipsoid) instantly with unit scaling. Free online volume calculator — no signup required.

Calculate interior angle, exterior angle, sum of interior angles, number of diagonals, area, perimeter, inradius, and circumradius for any regular polygon. Supports 3 to 10,000 sides with a live SVG preview and formula reference. Free online polygon calculator — no signup required.

Calculate monthly EMI, total interest payable, and total payment for any loan. Includes a full amortization table. Free online loan EMI calculator — no signup required.

Calculate monthly EMI, total interest, processing fee, and effective APR for any personal loan. Full amortization schedule included. Free online personal loan calculator — no signup required.

Calculate recurring deposit maturity amount, total interest, and month-by-month growth schedule. Uses quarterly compounding (Indian bank standard). Free online RD calculator — no signup required.

Enter an interest rate to find years to double your money, or enter years to find the required rate. Includes comparison table at 15 common rates and exact ln formula. Free online Rule of 72 calculator — no signup required.

Calculate DRIP returns vs cash dividends with year-by-year growth schedule. Enter share price, dividend yield, and years to see the compounding power of dividend reinvestment. Free online DRIP calculator — no signup required.

Enter your outstanding balance, APR, and minimum payment to see months to pay off and total interest paid. Compare minimum payments vs. fixed payments with a full payoff schedule. Free online credit card interest calculator.

Compare Avalanche vs. Snowball debt payoff strategies for multiple debts. Enter balances, interest rates, and minimum payments to see your debt-free date, total interest, and full monthly schedule. Free online debt payoff calculator — no signup required.

Calculate monthly mortgage payment, total interest, and amortization schedule from purchase price, down payment, interest rate, and term. Free online mortgage calculator — no signup required.

Calculate the maximum home loan amount you are eligible for based on monthly income, existing EMIs, interest rate, and tenure. FOIR-based calculation with multi-tenure comparison. Free online home loan eligibility calculator — no signup required.

Calculate PPF maturity amount, total interest earned, and year-by-year balance table for Public Provident Fund investments. Current PPF rate 7.1% — supports 15 to 50-year durations. Free online PPF calculator — no signup required.

Calculate the Internal Rate of Return (IRR) for any investment by entering a series of cash flows. Newton-Raphson iteration, NPV sensitivity table, payback period. Free online IRR calculator — no signup required.

Project your retirement corpus from current age, savings, monthly contribution, and expected return. Inflation-adjusted values, return rate comparison, 4% withdrawal income estimate. Free online retirement savings calculator — no signup required.

Calculate gratuity payable under the Payment of Gratuity Act 1972 from last drawn salary and years of service. Tax exemption analysis, tenure comparison, eligibility check. Free online gratuity calculator — no signup required.

Generate a slab-wise GST tax summary from invoice line items with CGST/SGST or IGST breakdown. Supports unlimited line items, all GST slabs, discounts, and HSN/SAC codes. Free online invoice tax summary generator — no signup required.

Calculate gross profit, operating income, net profit, and all margins from revenue, COGS, and operating expenses. Full P&L statement with margin analysis. Free online profit and loss calculator — no signup required.

Calculate sale price and savings from original price and discount percentage. Reverse mode: input final price to get discount %. Free online discount calculator — no signup required.

What is X% off Y? And: what % off is the current price from the original? Three modes: find final price, find discount %, and find original price. Free online percentage discount calculator — no signup required.

Calculate tip amount and total per person from bill amount, tip percentage, and number of people. Free online tip calculator — no signup required.

Calculate markup percentage and gross margin from cost and selling price. Five modes: cost + price, cost + markup %, cost + margin %, and reverse calculations. Free online markup margin calculator — no signup required.

Convert BTC to satoshis, ETH to wei and Gwei, SOL to lamports — and back. Live USD prices via CoinGecko. BigInt precision for exact large-integer conversions. Free online cryptocurrency unit calculator — no signup required.

Estimate business value using Revenue Multiple, EBITDA Multiple, and DCF methods. 10 industry presets (SaaS, e-commerce, fintech, manufacturing, and more) plus custom multiples. Free online business valuation calculator — no signup required.

Calculate Customer Acquisition Cost (CAC), Customer Lifetime Value (LTV), LTV:CAC ratio, and CAC payback period. Health benchmarking against the 3× industry standard. Free online CAC LTV calculator — no signup required.

Add or remove GST at 5%, 12%, 18%, or 28% from any price. Shows base price, GST amount, and total with CGST/SGST split. Free online GST calculator — no signup required.

Add VAT to a net price or remove VAT from a gross price instantly. Supports UK VAT (20%), EU VAT, UAE VAT (5%), Australian GST (10%), and 17+ global rates with custom rate option. Free online VAT calculator — no signup required.

Compare New Regime vs Old Regime income tax for FY 2025-26 (AY 2026-27). Slab-wise breakdown, rebate u/s 87A, surcharge, cess, and deductions (80C, 80D, HRA, NPS). Free online income tax calculator India — no signup required.

Calculate stamp duty and registration charges for 15 major Indian states — Maharashtra, Delhi, Karnataka, Tamil Nadu, UP, and more. Supports male, female, and joint ownership with gender-based concessions. Free online stamp duty calculator — no signup required.

Calculate your minimum and recommended freelance hourly, daily, and project rates from desired income, working hours, vacation, overhead %, and tax rate. Includes project rate guide and billable hours breakdown. Free online freelancer rate calculator — no signup required.

Calculate Return on Investment percentage from investment cost and net profit. Supports Standard ROI, Annualized ROI (per-year return), and Social ROI (SROI ratio). Formula display, return multiple, and comparison table. Free online ROI calculator — no signup required.

Calculate TDS rate and amount for 25+ sections including §194J (professional fees), §194C (contractor), §194I (rent), and §194A (interest). Shows threshold check, TDS amount, cess, and net payable. Free online TDS calculator India — no signup required.

Calculate break-even units, break-even revenue, and contribution margin ratio in three modes. Includes target profit units, margin of safety, and a live break-even chart. Free online break-even units calculator — no signup required.

Calculate STCG and LTCG tax on equity shares, mutual funds, real estate, and gold with FY 2024-25 Budget 2024 rates. Includes indexation with CII and ₹1.25L LTCG exemption. Free online capital gains tax calculator — no signup required.

Calculate GST with CGST/SGST split for intra-state and IGST for inter-state transactions. Supports all four India GST slabs (5%, 12%, 18%, 28%) with add/remove GST modes and all-slab comparison. Free online India GST calculator — no signup required.

Convert between 170+ currencies with real-time exchange rates via the Frankfurter API. Free online currency converter — no signup required.

Calculate the value of gold in grams, tolas, or troy ounces using live XAU/USD spot rates. Get gold value in INR and USD with 9K–24K purity options. Free online gold price calculator — no signup required.

Calculate ideal body weight using Hamwi, Devine, Robinson, and Miller formulas with metric and imperial units. Shows ±10% healthy range and current weight comparison. Free online IBW calculator — no signup required.

Enter systolic and diastolic readings to get your AHA blood pressure category — Normal, Elevated, Stage 1, Stage 2, or Hypertensive Crisis — with explanation and recommended action. Free online blood pressure interpreter — no signup required.

Calculate ideal bedtimes and wake-up times based on 90-minute sleep cycles. Three modes: from wake-up time, from bedtime, or from right now. Free online sleep time calculator — no signup required.

Predict next period date, see current cycle phase, and preview 6 upcoming cycles with fertile windows and ovulation dates. Free online period tracker calculator — no signup required.

Calculate five Karvonen training zones in BPM from age and resting heart rate. Supports Tanaka, Fox, and Gulati max HR formulas with zone descriptions and color-coded bar. Free online heart rate zone calculator — no signup required.

Estimate VO2 max using the Resting Heart Rate method (Uth-Sørensen formula) or Cooper 12-minute run test. ACSM fitness classification with age and gender norms. Free online VO2 max estimator — no signup required.

Calculate total UK alcohol units and estimated BAC from drink types, weight, and gender. 18 preset drinks, Widmark formula, UK drink-drive limit comparison, and hours to sober. Free online alcohol unit calculator — no signup required.

Calculate eGFR using CKD-EPI 2021 and creatinine clearance using Cockcroft-Gault. KDIGO CKD staging G1–G5 with management guidance. Supports mg/dL and μmol/L, metric and imperial. Free online creatinine clearance calculator — no signup required.

Calculate daily water intake recommendation based on weight, activity level, and climate. Results in litres, fl oz, and glass counts with an hourly hydration schedule. Free online water intake calculator — no signup required.

Calculate Body Mass Index with metric and imperial units. See your BMI value, position on the color-coded BMI scale, healthy weight range, and WHO classification. Free online BMI calculator — no signup required.

Calculate lean body mass (LBM), fat mass, FFMI, and protein targets from weight and body fat %. Metric and imperial units, body fat category, and body composition bar. Free online lean body mass calculator — no signup required.

Calculate body fat percentage using the US Navy method (neck, waist, height) or BMI method. Shows fat mass, lean mass, body composition bar, and category — Essential, Athletic, Fitness, Average, or Obese. Free online body fat calculator — no signup required.

Convert between 13 weight and mass units — mg, g, kg, tonne, oz, lb, stone, short ton, long ton, grain, carat, troy oz, troy lb. All-at-once conversion table. Free online weight converter — no signup required.

Convert between 10 speed units — m/s, km/h, mph, ft/s, knots, Mach, ft/min, km/s, m/min, and speed of light. All-at-once conversion table with quick-convert buttons. Free online speed converter — no signup required.

Convert between 16 data transfer rate units — bps, Kbps, Mbps, Gbps, Tbps, and byte equivalents (B/s, KB/s, MB/s, GB/s, TB/s), plus IEC binary units. Grouped all-at-once table. Free online data rate converter — no signup required.

Convert between 10 frequency units — Hz, kHz, MHz, GHz, THz, RPM, RPS, rad/s, CPM, BPM. All-at-once conversion table with quick-convert buttons. Free online frequency converter — no signup required.

Calculate waist-to-hip ratio (WHR) and cardiovascular risk classification using WHO standard thresholds. Sex-specific cutoffs, visual risk scale, and optional waist-to-height ratio. Free online WHR calculator — no signup required.

Calculate calories burned by activity type, duration, and body weight using the MET formula. Supports multi-activity sessions, food calorie equivalents, and weekly burn projections. 40+ activities. Free online calorie burn calculator — no signup required.

Calculate corrected (adjusted) age for premature babies from birth date and gestational age at birth. Shows developmental milestones, prematurity classification, and when to stop correcting. Free online corrected age calculator — no signup required.

Calculate your daily calorie deficit or surplus, projected weekly weight change, and 12-week weight loss or gain timeline. Includes milestone timelines and safety warnings. Free online calorie deficit calculator — no signup required.

Estimate vitamin D synthesis from sun exposure based on skin type, latitude, season, and body coverage. Shows IU synthesis, UV index, minutes for RDA, and safe exposure limit. Free online vitamin D calculator — no signup required.

Calculate your daily calorie target for weight loss, maintenance, or gain. Enter current weight, height, activity level, and goal to get BMR, TDEE, macro split, and a 12-week weight projection. Free online calorie intake calculator — no signup required.

Generate the Fibonacci sequence to any number of terms (up to 1000) with exact BigInt precision. Highlights prime Fibonacci numbers, shows golden ratio approximation, sum of all terms, and includes a Fibonacci number lookup. Supports 4 output formats. Free online Fibonacci sequence generator — no signup required.

Generate arithmetic, geometric, Fibonacci, square, cube, prime, triangular, or custom formula sequences up to 200 terms with sum, formula, and properties. Free online number sequence generator — no signup required.

Enter x-y data pairs to get slope, intercept, R², Pearson r, standard errors, residuals, scatter plot with regression line, and inline prediction widget. Free online linear regression calculator — no signup required.

Calculate P(A), P(A or B), P(A and B), P(not A), conditional probability, Bayes' theorem, at-least-one, and binomial probabilities with step-by-step solutions. Free online probability calculator — no signup required.

Find all real and complex roots of any polynomial up to degree 20 using Aberth-Ehrlich and Newton-Raphson methods. Shows factored form, residual verification, and conjugate pair detection. Free online polynomial root finder — no signup required.

Check if any integer is prime with step-by-step trial division proof, Miller-Rabin for large numbers, previous/next prime, prime gaps, and next 5 primes. Supports integers up to 10³⁰. Free online prime number checker — no signup required.

Convert any fraction to decimal with exact repeating decimal notation, overline display, percentage equivalent, mixed number form, and long division steps. Supports negative and improper fractions. Free online fraction to decimal converter — no signup required.

Full browser scientific calculator with trig (sin/cos/tan/arcsin/arccos/arctan), logarithms (log/ln/log₂), exponents, roots, factorials, hyperbolic functions, DEG/RAD mode, calculation history, and memory. Free online scientific calculator — no signup required.

Plot mathematical functions online — sin(x), cos(x), polynomials, logarithms, and more. Plot up to 6 functions simultaneously with interactive zoom and pan. Free online graphing calculator — no signup required.

Convert numbers between binary (base 2), octal (base 8), decimal (base 10), hexadecimal (base 16), and any base 2–36. Full multi-base table, bit-width analysis, custom base output, and BigInt arithmetic. Free online number base converter — no signup required.

Convert radioactivity units between Bq, kBq, MBq, GBq, TBq, Ci, mCi, µCi, nCi, pCi, dpm, dps, and Rd. Full all-units table and real-world reference activities. Free online radioactivity converter — no signup required.

Convert fuel consumption units between mpg (US), mpg (UK), L/100km, km/L, and more. Full all-units table, efficiency rating badge, and real-world vehicle references. Free online fuel consumption converter — no signup required.

Convert pressure units instantly between Pa, kPa, MPa, bar, atm, psi, mmHg, inHg, Torr, and 10 more units. Full all-units conversion table with every result. Free online pressure converter — no signup required.

Calculate when caffeine drops to a safe level for sleep based on intake time, amount, and metabolic sensitivity. Includes 14 drink presets, 24-hour decay chart, and latest cutoff time. Free online caffeine half-life calculator — no signup required.

Calculate estimated due date from LMP, conception date, IVF transfer, or ultrasound. Shows gestational week, trimester, progress, and milestone timeline. Free online pregnancy due date calculator — no signup required.

Convert steps to km and miles using your height and activity type. Estimates stride length, shows distance in all units, race context, and step milestone table. Free online steps to distance calculator — no signup required.

Calculate daily protein requirement by body weight, activity level, and goal — muscle building, fat loss, endurance, or recomposition. Includes meal distribution and food reference. Free online protein intake calculator — no signup required.

Calculate ovulation date, fertile window, peak fertility days, and next period start from your last period date and cycle length. Free online ovulation calculator — no signup required.

Calculate your baby's exact age in years, months, weeks, and days. Shows total days old, total weeks old, 12 milestone dates (100 days to 18th birthday), and next birthday countdown. Free online baby age calculator — no signup required.

Estimate Blood Alcohol Content using the Widmark formula. Enter drinks (12 presets), weight, sex, and hours elapsed to get current BAC, peak BAC, time to sober, and time to legal limit. Free online BAC calculator — no signup required.

Calculate Waist-to-Height Ratio (WHtR) with five risk zones, colour-coded scale, and waist reduction target. Supports cm and inches. Based on Ashwell & Hsieh thresholds. Free online WHtR calculator — no signup required.

Balance chemical equations by entering reactants and products in standard notation — uses Gaussian elimination for accurate integer coefficients. Free online chemical equation balancer.

Simulate AND, OR, NOT, NAND, NOR, XOR, XNOR, and BUFFER logic gates with real-time output, truth tables, and Boolean expressions — up to 8 gates simultaneously. Free online logic gate simulator.

Calculate Total Daily Energy Expenditure from age, height, weight, and activity level using the Mifflin-St Jeor equation — get BMR, maintenance calories, goal targets, and macros. Free online TDEE calculator.

Calculate Basal Metabolic Rate using Mifflin-St Jeor and Harris-Benedict formulas with side-by-side comparison. Optionally add body fat % for Katch-McArdle. Includes TDEE reference table for all activity levels. Free online BMR calculator — no signup required.

Calculate calories burned from steps using MET values. Shows distance, walking duration, fat grams burned, and a step goal comparison table for 2,000–15,000 steps. Metric and imperial units. Free online steps to calories calculator — no signup required.

Estimate your 1RM using six formulas — Epley, Brzycki, Lander, Lombardi, Mayhew, and O'Conner. Formula comparison table and percentage-based training load table from 60–100% 1RM. Free online 1 rep max calculator — no signup required.

Calculate daily protein, carbs, and fat targets from your TDEE and goal — cut, bulk, or maintain. Supports 4 macro split presets (balanced, high protein, low carb, high carb) and custom splits. Free online macro calculator — no signup required.

Calculate running pace, finish time, or distance from any two known values. Supports km and miles with automatic split times for 5K, 10K, half marathon, and marathon. Free online running pace calculator — no signup required.

Predict a child's adult height from father and mother heights using the Mid-Parent (Tanner) and Khamis-Roche formulas with a 95% prediction range. Supports metric and imperial units. Free online child height predictor — no signup required.

Calculate Wilks coefficient, Wilks2 (2020), IPF GL Points, and DOTS Score from body weight and powerlifting total (squat + bench + deadlift). Level classification from Beginner to World Class. Free online Wilks score calculator — no signup required.

Calculate Total/HDL, LDL/HDL, Triglycerides/HDL, and Non-HDL cholesterol ratios with cardiovascular risk interpretation based on AHA/ACC guidelines. Supports mg/dL and mmol/L. Free online cholesterol ratio calculator — no signup required.

Calculate voltage, current, resistance, or power from any two known electrical values — supports all 6 input combinations and SI prefixes (kΩ, mA, μW). Free online Ohm's Law calculator.

Calculate total resistance for resistors in series, parallel, and mixed series-parallel combinations. Add unlimited resistors, supports SI prefixes (kΩ, MΩ, mΩ) and real-time results. Free online resistors in series and parallel calculator.

Solve for speed, distance, or time from any two known values — 6 speed units, 7 distance units, 5 time units, cross-unit conversions, and human-readable time output. Free online speed distance time calculator.

Calculate pendulum period from length and gravity, or find the required length for a target period. Supports 10 planetary gravity presets, 5 length units, frequency, angular frequency, and planet comparison table. Free online pendulum period calculator.

Calculate the gravitational force between any two masses using Newton's law of universal gravitation (F = G × m₁ × m₂ / r²). Supports kg, solar masses, Earth masses, AU, and light-years with scientific notation. Free online gravitational force calculator.

Calculate range, maximum height, time of flight, and impact velocity for any projectile — enter initial velocity, launch angle, and optional initial height. Live trajectory graph and full formula reference. Free online projectile motion calculator.

Solve any SUVAT kinematics problem — enter any 3 of the 5 variables (displacement, initial velocity, final velocity, acceleration, time) and the calculator solves for the rest using constant-acceleration equations. Free online kinematics calculator.

Solve the thin lens equation and mirror equation for image distance, object distance, or focal length. Supports converging/diverging lenses and concave/convex mirrors. Computes magnification and classifies images as real/virtual, upright/inverted. Free online optics calculator.

Calculate buoyant force from object volume and fluid density using Archimedes’ principle (F = ρVg). Includes fluid and gravity presets, plus float/sink analysis with object mass. Free online buoyancy calculator.

Calculate the angle of refraction from the angle of incidence and refractive indices using Snell's law, or solve in reverse. Finds the critical angle, detects total internal reflection, and shows the speed of light in each medium with a live ray diagram and 10 optical medium presets. Free online refraction calculator.

Solve F = ma for force, mass, or acceleration from any two known values — supports Newtons, kilonewtons, pound-force, dynes, kilograms, slugs, m/s², ft/s², and g-force with a full unit conversion table. Free online Newton's Second Law calculator.

Calculate observed frequency, frequency shift, and wavelength change from source frequency, source velocity, observer velocity, and propagation medium. Blueshift/redshift classification and wave visualisation included. Free online Doppler effect calculator.

Solve v = fλ for wave speed, frequency, or wavelength — derives period, photon energy (E = hf), angular frequency, wave number, and EM spectrum band. Supports Hz–THz, nm–km, and m/s–c. Free online wave properties calculator.

Solve Q = CV and E = ½CV² for charge, energy, capacitance, or voltage from any two known values — supports farads to picofarads, volts to megavolts, and joules to watt-hours with a full SI breakdown. Free online capacitor charge energy calculator.

Solve P = F ÷ A for pressure, force, or area from any two known values — supports Pa, kPa, MPa, bar, psi, atm, mmHg, Torr for pressure, plus newtons, pound-force, and 5 area units with a full conversion table. Free online pressure force area calculator.

Calculate the molecular weight of any chemical formula using IUPAC 2021 atomic weights. Supports all 118 elements, parentheses, brackets, and hydrate notation — Free online molecular weight calculator.

Convert any date and time from one timezone to multiple timezones simultaneously with automatic DST handling — supports 80+ IANA timezones. Free online timezone converter.

Look up what any time zone abbreviation means — full name, UTC offset, DST status, and disambiguation notes for 90+ abbreviations across all regions. Free online time zone reference.

Browse all country and territory flag emojis with ISO codes, Unicode codepoints, HTML entities, and CSS values — search by country name or code and copy with one click. Free online flag emoji reference.

Reference guide for binary, octal, decimal, and hexadecimal number systems with examples, digit rules, and instant cross-base lookup. Free online number system reference.

Calculate sunrise, sunset, solar noon, and day length for any date and location using the NOAA solar position algorithm — supports polar day and polar night. Free online day length calculator.

Convert between 20+ length and distance units — mm, cm, m, km, in, ft, yd, mi, nautical miles, light-years, parsecs, and more. Free online length distance converter — no signup required.

Convert between 20 power units — watts, kilowatts, megawatts, horsepower (mechanical, metric, electric), BTU/hr, ft·lbf/s, tons of refrigeration, dBm, and more. Free online power converter — no signup required.

Convert between 15 time units — milliseconds, seconds, minutes, hours, days, weeks, months, years, decades, centuries, and millennia. Free online time converter — no signup required.

Convert between 15 force units — newtons, kilonewtons, pound-force, kilogram-force, dyne, poundal, kip-force, ounce-force, and more. Free online force converter — no signup required.

Convert luminance and illuminance units — lux, foot-candle, phot, nox, nit, cd/m², foot-lambert, stilb, apostilb, lambert, and more. Free online luminance illuminance converter — no signup required.

Convert between US, UK/AU, EU/ISO, Japan ring sizes and diameter/circumference in mm. Includes a printable ring sizer and full reference chart. Free online ring size converter — no signup required.