Capacitor Charge & Energy Calculator
Calculate capacitor charge and energy online for free. Enter any two of capacitance, voltage, charge, or energy and our capacitor charge energy calculator instantly solves the rest using Q = CV and E = ½CV². Supports farads to picofarads, volts to megavolts, and joules to watt-hours. All calculations run locally in your browser with no signup required.
Enter any two of capacitance, voltage, charge, or energy to instantly find the other two using Q = C × V and E = ½ C V². All calculations run locally in your browser — no signup required.
Formula Reference
All calculations run locally in your browser. No data is ever sent to a server.
Why Use Our Capacitor Charge & Energy Calculator?
Instant Capacitor Charge & Energy Calculations
Solve for charge, energy, capacitance, or voltage in real time as you type. Our capacitor charge energy calculator updates every value instantly with no page reload or submit button.
Secure Capacitor Calculator Online
Every calculation runs entirely in your browser. Your values never leave your device, so you can use our capacitor charge energy calculator online with complete privacy and no data collection.
Capacitor Calculator Online — No Installation
Use our capacitor charge energy calculator directly in any browser with zero downloads, plugins, or software required. Works on desktop, tablet, and mobile for engineering on the go.
Any Two Inputs, Full Multi-Unit Support
Enter any two of capacitance, voltage, charge, or energy and the capacitor charge energy calculator finds the rest. Supports F–pF, V–MV, C–pC, and J–Wh with a complete SI breakdown.
Common Use Cases for Capacitor Charge & Energy Calculator
Electronics Homework & Exam Prep
Students use our capacitor charge energy calculator to verify Q = CV and E = ½CV² homework answers, check circuit-analysis problems, and build intuition for how capacitance, voltage, charge, and stored energy relate.
Circuit Design & PCB Engineering
Electronics engineers calculate the charge and energy stored in decoupling, bypass, and bulk capacitors. Our capacitor charge energy calculator helps size components for power-supply filtering and energy reserves.
Power Electronics & Energy Storage
Design DC-link and snubber capacitors by calculating stored energy at a given voltage. Use our capacitor charge energy calculator to compare energy capacity across capacitor values in supercapacitor and inverter designs.
Flash & Pulse Circuits
Calculate the energy delivered by a camera flash, defibrillator, or pulsed-laser capacitor bank. The capacitor charge energy calculator converts between joules and watt-hours so you can verify discharge energy precisely.
Audio & Filter Design
Determine the charge and energy in coupling and crossover capacitors at signal voltage levels. Our capacitor charge energy calculator supports nF and pF inputs common in audio and RF filter networks.
Lab Work & Physics Experiments
Verify experimental measurements of capacitor charge and energy against theory. Enter measured voltage and capacitance and the capacitor charge energy calculator gives the expected charge and stored energy instantly.
Understanding Capacitor Charge and Energy
What is Capacitor Charge and Energy?
A capacitor stores electrical energy in the electric field between its plates. The charge it holds is given by Q = C × V, where C is capacitance in farads and V is the voltage across the plates. The energy stored is given by E = ½ × C × V², which can also be written as E = ½QV or E = Q²/(2C). Our capacitor charge energy calculator uses these relationships to solve for any two unknowns when you provide any two known values among capacitance, voltage, charge, and energy — all computed in SI units internally for maximum accuracy.
How Our Capacitor Charge & Energy Calculator Works
- Select which two values you know: Choose your known pair — for example Capacitance + Voltage, or Charge + Energy — from the selector. The capacitor charge energy calculator enables exactly those two input fields and computes the rest.
- Enter your values with units: Type your two known quantities and pick their units. The capacitor charge energy calculator supports farads down to picofarads, volts up to megavolts, coulombs down to picocoulombs, and joules through watt-hours — all converted to SI before computing.
- Read the computed results instantly: The two unknown quantities appear in highlighted result cards, with a full SI breakdown of all four values below. Change any unit and the capacitor charge energy calculator re-converts immediately.
What Gets Calculated
- Charge (Q = C × V): The electric charge stored on the capacitor plates, in coulombs, millicoulombs, microcoulombs, nanocoulombs, or picocoulombs.
- Energy (E = ½ C V²):The energy stored in the capacitor's electric field, in joules, millijoules, microjoules, kilojoules, or watt-hours.
- Capacitance (C = Q ÷ V):The capacitor's ability to store charge per volt, in farads, millifarads, microfarads, nanofarads, or picofarads.
- Voltage (V = Q ÷ C): The potential difference across the capacitor plates, in volts, millivolts, kilovolts, or megavolts.
Important Notes on Capacitor Energy
The energy stored in a capacitor scales with the square of the voltage, so doubling the voltage quadruples the stored energy. This is why charged capacitors — especially large bulk and high-voltage types — can be dangerous even after a circuit is powered off. Our capacitor charge energy calculator assumes an ideal capacitor at a fixed DC voltage and does not account for dielectric losses, leakage current, equivalent series resistance (ESR), or temperature derating. For real components, always consult the manufacturer datasheet and observe the rated maximum voltage.
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Frequently Asked Questions About Capacitor Charge & Energy Calculator
A capacitor charge energy calculator is a tool that solves the capacitor equations Q = C × V and E = ½ C V² for any unknowns. Enter any two of capacitance, voltage, charge, or energy and our capacitor charge energy calculator instantly finds the remaining two values. It runs entirely in your browser with no signup required.
The charge stored in a capacitor is calculated with Q = C × V, where Q is charge in coulombs, C is capacitance in farads, and V is voltage in volts. For example, a 100 µF capacitor at 12 V stores Q = 100×10⁻⁶ × 12 = 1.2 mC. Our capacitor charge energy calculator handles all the unit conversions automatically.
The energy stored in a capacitor is E = ½ × C × V². You can also use E = ½ Q V or E = Q² ÷ (2C) if you know the charge instead of capacitance. For example, a 100 µF capacitor at 12 V stores E = ½ × 100×10⁻⁶ × 12² = 7.2 mJ. The capacitor charge energy calculator computes this instantly in joules, mJ, µJ, kJ, or Wh.
Because energy is the integral of charge with respect to voltage as the capacitor charges. As voltage rises, each additional bit of charge is added at a higher potential, so the total energy grows with V². This means doubling the voltage quadruples the stored energy — an important safety consideration our capacitor charge energy calculator makes easy to see.
Our capacitor charge energy calculator supports farads, millifarads, microfarads, nanofarads, and picofarads for capacitance; volts, millivolts, kilovolts, and megavolts for voltage; coulombs down to picocoulombs for charge; and joules, millijoules, microjoules, kilojoules, and watt-hours for energy. Every result is also shown in SI base units.
Yes. Select the "Charge + Energy" mode and the capacitor charge energy calculator solves for both voltage (V = 2E ÷ Q) and capacitance (C = Q ÷ V). The tool supports all six possible known-value pairs, so you can start from whichever two quantities you have measured or specified.
Absolutely. All calculations run entirely in your browser using JavaScript. No values are ever sent to any server. Your inputs stay on your device, making our capacitor charge energy calculator online completely private and secure.
Yes, our capacitor charge energy calculator is 100% free with no signup, no premium tier, no usage limits, and no restrictions. Use it unlimited times for homework, lab work, or professional circuit design.
No — the capacitor charge energy calculator models an ideal capacitor at a fixed DC voltage. It does not account for leakage current, equivalent series resistance (ESR), dielectric absorption, or voltage/temperature derating. For real components, always check the manufacturer datasheet and never exceed the rated voltage.