Battery Capacity Converter

Convert battery capacity between amp-hours, milliamp-hours, watt-hours, kilowatt-hours, volts, watts, and runtime. Use this converter for car batteries, EV batteries, lithium batteries, power stations, deep cycle batteries, and 12V systems.

Convert Battery Capacity

100 Ah at 12 V = 1200 Wh
Your battery capacity conversion result will appear here.

Common battery capacity formulas

Amp-hours to watt-hours:
Wh = Ah × volts

Watt-hours to amp-hours:
Ah = Wh ÷ volts

Milliamp-hours to amp-hours:
Ah = mAh ÷ 1000

Runtime estimate:
hours = usable Wh ÷ load watts

Where battery capacity conversions are used

Battery capacity conversions are useful for car batteries, EV batteries, RV batteries, marine batteries, solar batteries, deep cycle batteries, portable power stations, lithium battery packs, inverters, and 12V accessories.

Use this converter as an estimate. Actual runtime depends on battery chemistry, temperature, discharge rate, inverter losses, battery age, and usable depth of discharge.

What your battery capacity result means

Your result shows the entered battery capacity converted into the selected unit. The converter also displays amp-hours, milliamp-hours, watt-hours, kilowatt-hours, usable energy, and estimated runtime based on the load entered.

Battery capacity ratings are not always fully usable. Lead-acid batteries, lithium batteries, EV packs, and power stations may have different usable capacity limits and efficiency losses.

Battery capacity converter tips

Frequently asked questions

How do I convert Ah to Wh?

Multiply amp-hours by voltage. For example, 100Ah at 12V equals 1200Wh.

How do I convert Wh to Ah?

Divide watt-hours by voltage. For example, 1200Wh at 12V equals 100Ah.

How do I convert mAh to Ah?

Divide milliamp-hours by 1000. For example, 5000mAh equals 5Ah.

How do I estimate battery runtime?

Divide usable watt-hours by the load in watts. For example, 1200Wh powering 100W lasts about 12 hours before losses.

Is Ah or Wh better for comparing batteries?

Wh is usually better when comparing batteries with different voltages because it measures stored energy.