Skip to content
Log in Calculators

Battery Capacity Converter (Ah, Wh, kWh)

Convert amp-hours to watt-hours or kilowatt-hours and back at any nominal voltage, with the amp-hours per kWh factor.

Inputs

Voltage and capacity

Battery or bank voltage. Use the datasheet nominal value: 12 V, 12.8 V LiFePO4, 24 V, 48 V, 51.2 V.

Pick the direction that matches the figure you already have.

Amp-hour rating at the nominal voltage. Used when converting amp-hours to watt-hours.

Watt-hour rating. Used when converting watt-hours to amp-hours.

Result

Amp-hours per kWh at this voltage
—
Capacity in amp-hours
—
Capacity in kilowatt-hours
—
Capacity in watt-hours
—

What to check

  • Nominal voltage, not fully charged voltage: a 12 V lead-acid battery rests near 12.6-12.8 V and a LiFePO4 unit near 13.2 V.
  • Whether the amp-hour rating is quoted at the 20-hour rate, a 1C rate, or a reserve-capacity figure; the numbers differ.
  • Whether the figure is nameplate or usable kWh at the intended depth of discharge.
  • Temperature: amp-hour capacity falls in cold conditions, so a cold-weather comparison needs the derated rating.

Related calculators

Unit conversion only. Amp-hour ratings are discharge-rate and temperature dependent, so the converted energy is a nominal figure, not a measured performance guarantee. Confirm ratings at the manufacturer stated discharge rate and the installed system voltage before relying on the comparison.

Saved calculations

Keep the assumptions with the result.

Save this calculation to return to the inputs, result, and report anytime.

Sign in to save Create account

Sign in or create an account to save this calculation.