Ideal Body Weight Calculator
Calculate your ideal body weight using four established medical formulas — Hamwi, Devine, Robinson, and Miller. Enter your height and biological sex to get IBW results from all four formulas with ±10% healthy ranges, the average across all formulas, and an optional comparison to your current weight. Supports metric and imperial units — free, private, and no signup required.
Enter your height and gender to calculate your ideal body weight using four established medical formulas — Hamwi, Devine, Robinson, and Miller. Optionally enter your current weight to see how you compare. All calculations run locally in your browser with no signup required.
IBW formulas differ by biological sex
e.g. 170 cm
Compare your weight to the ideal range
- IBW formulas are clinical tools — not targets for everyone. Athletes and muscular individuals may healthily exceed these values.
- These formulas were developed for adults and may not apply to children, elderly, or pregnant individuals.
- Consult a healthcare professional for personalized weight and health guidance.
Why Use Our Ideal Body Weight Calculator?
Instant Ideal Body Weight Calculation
Enter your height and biological sex to instantly compute your ideal body weight using all four established medical formulas — Hamwi, Devine, Robinson, and Miller. The ideal body weight calculator shows individual results, a ±10% healthy range, and the average across all formulas.
Secure Ideal Body Weight Calculator Online
The ideal body weight calculator runs entirely in your browser. Your height, weight, and health measurements are never sent to any server — no data collection, no tracking, completely private.
Ideal Body Weight Calculator — No Installation
Use the ideal body weight calculator directly in any modern browser with no downloads, apps, or plugins required. Supports both metric (cm, kg) and imperial (ft + in, lbs) units for worldwide use.
Four Formulas with Current Weight Comparison
The ideal body weight calculator computes Hamwi, Devine, Robinson, and Miller results side by side with formula descriptions. Optionally enter your current weight to see exactly how much above or below your ideal range you are — 100% free forever.
Common Use Cases for Ideal Body Weight Calculator
Clinical Drug Dosing
Many medications — particularly in anaesthesia, oncology, and critical care — are dosed based on ideal body weight rather than actual weight to avoid toxicity in overweight patients. The ideal body weight calculator provides the Devine formula result most commonly used for drug dosing calculations.
Nutritional Assessment
Dietitians and nutritionists use the ideal body weight calculator to establish a reference weight for calculating caloric needs, protein requirements, and macronutrient targets. IBW is a key input for the Mifflin-St Jeor and Harris-Benedict BMR formulas.
Weight Loss Goal Setting
Use the ideal body weight calculator to set a realistic, medically grounded weight loss target. Seeing your ideal weight range from four independent formulas gives you a clear, evidence-based goal rather than an arbitrary number.
Fitness and Body Composition Planning
Personal trainers and fitness coaches use the ideal body weight calculator alongside body fat percentage measurements to set appropriate weight targets for clients. IBW provides a baseline reference for lean mass and body composition goals.
Ventilator and Respiratory Therapy
In respiratory therapy and mechanical ventilation, tidal volume is calculated based on predicted body weight (PBW), which uses the Devine formula. The ideal body weight calculator provides this value instantly for clinical reference.
Health Insurance and Wellness Programs
Many corporate wellness programs and health insurance assessments use ideal body weight as a benchmark alongside BMI. The ideal body weight calculator provides a more nuanced view than BMI alone by showing results across four validated formulas.
Understanding Ideal Body Weight
What is Ideal Body Weight?
Ideal Body Weight (IBW) is a clinically derived estimate of the optimal weight for a person of a given height and biological sex. Unlike BMI, which uses a single formula, IBW is calculated using four established medical formulas — Hamwi (1964), Devine (1974), Robinson (1983), and Miller (1983) — each developed for specific clinical applications such as drug dosing, nutritional assessment, and respiratory therapy. Our ideal body weight calculator computes all four formulas simultaneously and shows the average, giving you a comprehensive reference range rather than a single number — all running instantly in your browser with no signup required.
How Our Ideal Body Weight Calculator Works
- Enter Your Height and Sex: Select your unit system (metric or imperial), enter your height, and select your biological sex. The ideal body weight calculator uses sex-specific coefficients because the four IBW formulas have different base weights and per-inch increments for males and females.
- Instant Browser-Based Calculation:Click “Calculate Ideal Body Weight” and the calculator applies all four formulas simultaneously in your browser. No data is sent to any server — your measurements stay completely private on your device.
- Review Results Across All Four Formulas: The ideal body weight calculator displays the IBW and ±10% healthy range for each formula, the average across all four, and — if you entered your current weight — how much above or below your ideal range you currently are.
The Four IBW Formulas Explained
- Hamwi Formula (1964): The original IBW formula, developed for clinical use. Uses 48 kg (male) or 45.5 kg (female) as the base at 5 feet, adding 2.7 kg (male) or 2.2 kg (female) per inch above 5 feet. Widely used in nutrition and pharmacy.
- Devine Formula (1974): The most commonly used IBW formula in medicine, particularly for drug dosing and mechanical ventilation tidal volume calculations. Uses 50 kg (male) or 45.5 kg (female) as the base, adding 2.3 kg per inch above 5 feet for both sexes.
- Robinson Formula (1983): A revision of the Devine formula that produces slightly lower estimates, particularly for taller individuals. Uses 52 kg (male) or 49 kg (female) as the base, adding 1.9 kg (male) or 1.7 kg (female) per inch above 5 feet.
- Miller Formula (1983): Tends to produce higher estimates than the other formulas, particularly for shorter individuals. Uses 56.2 kg (male) or 53.1 kg (female) as the base, adding 1.41 kg (male) or 1.36 kg (female) per inch above 5 feet.
Important Limitations of Ideal Body Weight
The IBW formulas were developed in the 1960s–1980s primarily for clinical drug dosing and nutritional assessment — not as personal weight loss targets. They do not account for muscle mass, bone density, age, ethnicity, or body composition. Athletes and muscular individuals may healthily exceed IBW values. The formulas also have reduced accuracy for individuals under 5 feet tall, as they were not validated for shorter heights. Always consult a healthcare professional for personalized weight and health guidance beyond what the ideal body weight calculator provides.
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Frequently Asked Questions About Ideal Body Weight Calculator
An ideal body weight calculator estimates the optimal weight for a person of a given height and biological sex using established medical formulas. Our ideal body weight calculator computes all four major formulas — Hamwi, Devine, Robinson, and Miller — simultaneously and shows the average, giving you a comprehensive reference range. It runs entirely in your browser with no signup required.
No single formula is universally "most accurate" — each was developed for a specific clinical context. The Devine formula is most commonly used in medicine for drug dosing and mechanical ventilation. The Hamwi formula is widely used in nutrition. The Robinson and Miller formulas provide revised estimates. Our ideal body weight calculator shows all four so you can see the full range rather than relying on one formula.
BMI (Body Mass Index) is a ratio of weight to height squared that classifies weight into categories. Ideal body weight (IBW) is a specific weight estimate derived from height and sex using clinical formulas. BMI tells you which category your current weight falls into; IBW tells you a target weight range. Both are screening tools with limitations — neither accounts for muscle mass or body composition.
The four IBW formulas use different base weights and per-inch increments for males and females, reflecting average differences in bone density, muscle mass, and body composition between biological sexes. For example, the Devine formula uses 50 kg as the male base and 45.5 kg as the female base at 5 feet. Selecting the correct biological sex ensures the most clinically appropriate IBW estimate.
Absolutely. The ideal body weight calculator runs 100% locally in your browser. Your height, weight, and all health measurements are never sent to any server, stored in a database, or tracked in any way. Everything stays completely private on your device.
Yes — the ideal body weight calculator is 100% free with no signup, no account, and no usage limits. Calculate ideal body weight for any height and sex as many times as you need, completely free forever. There are no ads, no premium tiers, and no data collection.
The ±10% range shown for each formula represents the clinically accepted healthy weight range around the IBW value. For example, if the Devine formula gives an IBW of 70 kg, the healthy range is 63–77 kg. Most clinical guidelines consider a weight within 10% of IBW to be within the normal range for that formula.
No. The Hamwi, Devine, Robinson, and Miller formulas were developed and validated for adults. They are not appropriate for children or adolescents, whose ideal weight depends on age and developmental stage. For children, use age-specific growth charts from the WHO or CDC instead.
Each formula was developed independently by different researchers using different study populations and methodologies. The Hamwi formula (1964) was developed for nutritional assessment; the Devine formula (1974) for drug dosing; Robinson and Miller (both 1983) as revisions with updated coefficients. The differences are typically small — usually within 2–5 kg — which is why the average across all four formulas is a useful reference.