Capacitor Calculator
Charge, voltage and capacitance from any two of the three — plus the energy stored.
What is Capacitor?
A capacitor stores charge in proportion to the voltage across it: Q = C·V, the defining relation of capacitance. Any two of charge, voltage and capacitance determine the third, and the page also reports the energy stored (½CV²) — which is not a curiosity: it is the quantity that decides whether a capacitor is a shock hazard after the supply is disconnected, and a 400 V 470 µF part holds 37.6 joules.
How it works
The pair of values supplied selects the rearrangement — C·V for charge, Q ÷ C for voltage, Q ÷ V for capacitance — and the substitution is printed with the numbers in it. Charge is entered in milli-coulombs and capacitance in micro-farads because that is how the parts are sold, and both are converted to coulombs and farads before the arithmetic so no page can mix a prefix into an equation.
- Enter your input. Type or paste your input into the field above — the tool responds instantly.
- Review the result. Output updates live as you type. Everything runs entirely in your browser.
- Copy or download. Use the Copy button to grab the result, or Download to save it as a file.
Examples
Realistic sample
Type or paste any realistic input — the tool computes the result locally and instantly.
Common mistakes
Expecting a server round-trip
Nothing is uploaded — every tool in this category runs entirely in your browser.