Farads to kWh Calculator

By: Patrick Myers Patrick Myers is the CEO and Founder of Calculator Academy. He has over eight years of experience developing online calculators and holds a B.S. in Mechanical Engineering. His work focuses on formula implementation, calculator accuracy, unit conversions, and creating practical tools that are easy to use.

Last Updated: July 6, 2026
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This calculator was built with Calculator Academy’s community calculator studio with AI assistance, and was reviewed by the Calculator Academy team before publication.

About the Farads to kWh Calculator

This tool estimates the ideal energy stored in a capacitor or capacitor bank from its capacitance and terminal voltage. It is useful for electronics students, engineers, hobbyists, and anyone comparing capacitor storage in joules, watt-hours, or kilowatt-hours.

How to use this calculator

  1. Enter the total capacitance in farads.
  2. Enter the voltage across the capacitor terminals in volts.
  3. Click Calculate to compute the stored energy.
  4. Review the result in kWh, Wh, and joules.
  5. Click Reset to restore the default values of 1000 F and 48 V.

How it works

Capacitance by itself does not define stored energy; the voltage is also required. The calculator uses the standard capacitor energy equation E = ½CV², where E is energy in joules, C is capacitance in farads, and V is voltage in volts.

After calculating joules, the tool converts energy to watt-hours by dividing by 3,600, since 1 Wh equals 3,600 J. It then converts to kilowatt-hours by dividing joules by 3,600,000.

The result is an ideal stored-energy estimate. Real usable energy can be lower due to voltage limits, discharge cutoff, equivalent series resistance, balancing circuits, leakage, and power converter efficiency.

Example calculation

For the default values of 1000 F and 48 V, the energy is 0.5 × 1000 × 48² = 1,152,000 J. Dividing by 3,600 gives 320 Wh, and dividing by 3,600,000 gives 0.32 kWh.

Frequently asked questions

Can farads be converted directly to kWh?

No. Farads measure capacitance, not energy, so voltage is required to calculate stored energy.

Why does voltage have such a large effect on the result?

Energy is proportional to voltage squared, so doubling the voltage increases stored energy by four times for the same capacitance.

Is the calculated kWh the usable energy I can get from the capacitor?

Not exactly. The calculator gives ideal stored energy; usable output is often lower because of discharge limits, losses, ESR, and converter efficiency.

What happens if capacitance or voltage is zero?

If either value is zero, the stored energy is zero because the formula E = ½CV² requires both capacitance and voltage.

Does this work for a capacitor bank?

Yes, if you enter the total equivalent capacitance of the bank and the voltage across the bank terminals.