Calculators
Capacitor Energy Calculator
Solve for stored capacitor energy, capacitance, or voltage using consistent units locally in your browser.
Choose what to solve for, then enter the other two values using consistent units (for example, farads with volts for joules). This models an ideal capacitor with no leakage or equivalent series resistance. Calculations run locally in your browser; your values are not uploaded or stored.
Solve stored capacitor energy without uploading your values.
Enter capacitance with voltage to calculate stored energy, energy with voltage to calculate capacitance, or energy with capacitance to calculate voltage, using consistent units, such as farads with volts for joules. The calculator applies energy = 0.5 x capacitance x voltage squared and shows the matching result locally without being uploaded or stored.
Frequently Asked Questions
Everything you need to know about this tool, how it works, and privacy.
Which formulas does the capacitor energy calculator use?
It uses energy = 0.5 x capacitance x voltage squared, capacitance = 2 x energy / voltage squared, and voltage = square root of (2 x energy / capacitance). For example, a capacitance of 0.001 farads at 10 volts stores 0.05 joules of energy.
Which units should I use?
Use the same capacitance and voltage units on both inputs, such as farads with volts for joules. The answer is reported in the matching combined energy, capacitance, or voltage unit.
Which inputs are accepted?
Enter values of zero or greater up to 1,000,000,000,000. Voltage must not be zero when solving for capacitance, and capacitance must be greater than zero when solving for voltage. Missing or non-numeric entries show a clear error instead of a result.
Does this model a real capacitor?
No. It models an ideal capacitor with no leakage, no equivalent series resistance, and no dielectric absorption, so real-world capacitors with losses will store and return slightly less usable energy.
Do my values stay private?
Yes. The calculation and copy action run locally in your browser. CodeASystem does not upload or store the values you enter.