Capacitor Energy Calculator
Enter capacitance in farads and voltage in volts to calculate stored energy in joules.
A QUICK WALKTHROUGH
How to use this tool
- Enter the stated measurements in the specified units.
- Select Calculate to evaluate the formula.
- Review the result and the model limitations.
Formula and scope
Formula: U = ½CV². C is capacitance in farads, V is voltage in volts, and U is energy in joules. This is the ideal-capacitor model. Independent reference: OpenStax University Physics Volume 2, Energy Stored in a Capacitor (https://openstax.org/books/university-physics-volume-2/pages/8-3-energy-stored-in-a-capacitor). Inputs use SI units and must be finite; C > 0 and V ≥ 0. It does not account for leakage, dielectric losses, equivalent series resistance, or component ratings.
GOOD TO KNOW
Common questions
What assumptions does this use?
Ideal capacitor only; real losses and voltage limits are not modelled.
Are values uploaded?
No. The calculation runs locally in this browser.