--- title: "Ah to Wh Calculator: Amp Hours to Watt Hours (and Back)" description: "Convert amp hours to watt hours (Ah to Wh), Wh to Ah and Ah to kWh for any battery voltage. Wh = Ah × V, with charts for 12 V, 24 V and 48 V batteries." canonical: https://batteryruntimecalculator.com/ah-to-wh-calculator language: en updated: 2026-11-10 source_revision: 59f9d32 maintainer: Battery Runtime Calculator (hello@batteryruntimecalculator.com) --- # Ah to Wh Calculator Convert amp-hours to watt-hours, watt-hours to amp-hours, and either to kWh, for any battery voltage. Updated November 10, 2026 Quick answer Watt-hours = amp-hours × volts. A 12 V 100 Ah battery holds **1,200 Wh** (1.2 kWh). To go back, divide by the voltage: 1,000 Wh at 12 V is **83.3 Ah**. Capacity in watt-hours 1,200 Wh 100 Ah at 12 V Amp-hours 100 Ah Milliamp-hours 100,000 mAh Watt-hours 1,200 Wh Kilowatt-hours 1.2 kWh 100 Ah × 12 V = 1,200 Wh ## How to convert amp-hours to watt-hours Multiply the amp-hours by the battery voltage: ``` Wh = Ah × V ``` Example: a 24 V 200 Ah battery bank stores 200 × 24 = 4,800 Wh, or 4.8 kWh. For milliamp-hours, divide by 1,000 first, or use the [mAh to Wh calculator](https://batteryruntimecalculator.com/mah-to-wh-calculator). ## How to convert watt-hours to amp-hours Divide the watt-hours by the voltage: ``` Ah = Wh ÷ V Ah = kWh × 1,000 ÷ V ``` Example: a 2,048 Wh LiFePO4 power station built on a 12.8 V battery holds 2,048 ÷ 12.8 = 160 Ah. The voltage must be the battery’s own voltage, not the 120 V or 230 V of the AC outlets. ## Ah to Wh conversion chart Watt-hours for common battery sizes at the nominal voltages they are sold at. 12.8 V and 51.2 V are the real voltages of “12 V” and “48 V” LiFePO4 batteries. | Capacity | 12 V | 12.8 V | 24 V | 48 V | 51.2 V | | --- | --- | --- | --- | --- | --- | | 7 Ah | 84 Wh | 90 Wh | 168 Wh | 336 Wh | 358 Wh | | 9 Ah | 108 Wh | 115 Wh | 216 Wh | 432 Wh | 461 Wh | | 20 Ah | 240 Wh | 256 Wh | 480 Wh | 960 Wh | 1,024 Wh | | 50 Ah | 600 Wh | 640 Wh | 1,200 Wh | 2,400 Wh | 2,560 Wh | | 100 Ah | 1,200 Wh | 1,280 Wh | 2,400 Wh | 4,800 Wh | 5,120 Wh | | 150 Ah | 1,800 Wh | 1,920 Wh | 3,600 Wh | 7,200 Wh | 7,680 Wh | | 200 Ah | 2,400 Wh | 2,560 Wh | 4,800 Wh | 9,600 Wh | 10,240 Wh | | 280 Ah | 3,360 Wh | 3,584 Wh | 6,720 Wh | 13,440 Wh | 14,336 Wh | | 300 Ah | 3,600 Wh | 3,840 Wh | 7,200 Wh | 14,400 Wh | 15,360 Wh | ## kWh to Ah chart for home and solar batteries Home batteries are rated in kilowatt-hours. This is the same capacity in amp-hours at each system voltage. | Energy | 12 V | 24 V | 48 V | 51.2 V | | --- | --- | --- | --- | --- | | 1 kWh | 83 Ah | 42 Ah | 21 Ah | 20 Ah | | 2.5 kWh | 208 Ah | 104 Ah | 52 Ah | 49 Ah | | 5 kWh | 417 Ah | 208 Ah | 104 Ah | 98 Ah | | 10 kWh | 833 Ah | 417 Ah | 208 Ah | 195 Ah | | 13.5 kWh | 1,125 Ah | 563 Ah | 281 Ah | 264 Ah | | 15 kWh | 1,250 Ah | 625 Ah | 313 Ah | 293 Ah | ## Why compare batteries in watt-hours Amp-hours only compare batteries of the same voltage. A 24 V 100 Ah battery stores twice the energy of a 12 V 100 Ah battery, though both say “100 Ah”. Watt-hours measure energy directly, so they let you compare a 12 V RV battery, a 48 V home battery and a portable power station on equal terms, and they plug straight into a runtime estimate: runtime (h) ≈ usable Wh ÷ load (W). - **Rated is not usable.** The Wh figure is the rated capacity. You can use about 90% of it from LiFePO4 and about 50% from lead-acid if you want it to last. - **Series adds volts, parallel adds amp-hours.** Two 12 V 100 Ah batteries hold 2,400 Wh whichever way they are wired: 24 V 100 Ah in series or 12 V 200 Ah in parallel. Once you have watt-hours, the [battery runtime calculator](https://batteryruntimecalculator.com/) tells you how long they will run a load, and the [battery capacity calculator](https://batteryruntimecalculator.com/battery-size-calculator) works out how many you need. The method is on [how battery runtime is calculated](https://batteryruntimecalculator.com/how-battery-runtime-is-calculated). ## Frequently asked questions ### How many watt-hours is a 100Ah battery? It depends on the voltage. A 12 V 100 Ah lead-acid battery holds 1,200 Wh, a 12.8 V 100 Ah LiFePO4 battery 1,280 Wh, a 24 V 100 Ah battery 2,400 Wh and a 48 V 100 Ah battery 4,800 Wh (4.8 kWh). ### How do I convert watt-hours to amp-hours? Divide the watt-hours by the battery voltage: Ah = Wh ÷ V. A 1,000 Wh power station with a 12.8 V battery inside holds about 78.1 Ah; a 1,000 Wh battery at 24 V is about 41.7 Ah. ### How many amp-hours is a 5 kWh battery? A 5 kWh battery at 48 V holds about 104 Ah, and at the 51.2 V of a 16-cell LiFePO4 home battery about 97.7 Ah. The same 5 kWh at 12 V would be about 417 Ah. Multiply kWh by 1,000 and divide by the voltage. ### Is a 12V 100Ah battery 1,200 Wh or 1,280 Wh? Both are used. Lead-acid batteries have a nominal 12 V, so 100 Ah is 1,200 Wh. LiFePO4 batteries sold as “12 V” are really 12.8 V (four 3.2 V cells), so 100 Ah is 1,280 Wh. Use the voltage printed on the battery label for an exact figure. ### Can I convert Ah to Wh without knowing the voltage? No. An amp-hour measures charge and a watt-hour measures energy, and voltage links the two (watts = amps × volts). The same 100 Ah is 370 Wh in a 3.7 V lithium-ion pack and 4,800 Wh in a 48 V battery bank. If you only know the battery type, use its nominal voltage: 1.2 V for NiMH, 3.6–3.7 V for lithium-ion, 3.2 V per LiFePO4 cell, 2 V per lead-acid cell. ## More battery calculators - [Battery runtimeRuntime for any battery and load, in Ah or Wh, AC or DC.](https://batteryruntimecalculator.com/) - [Battery life (mAh)mAh and mA to hours, with sleep current and duty cycle.](https://batteryruntimecalculator.com/battery-life-calculator) - [Battery sizeHours you need in, battery Ah, Wh and count out.](https://batteryruntimecalculator.com/battery-size-calculator) - [Solar battery bankDaily kWh and days of autonomy to a battery bank size.](https://batteryruntimecalculator.com/solar-battery-calculator) - [UPS runtimeBackup minutes for a computer, router or NAS on a UPS.](https://batteryruntimecalculator.com/ups-runtime-calculator) - [Inverter backupHome inverter backup hours for 150 Ah to 220 Ah batteries.](https://batteryruntimecalculator.com/inverter-battery-backup-calculator) - [Power station runtimeWh rating to runtime for portable power stations.](https://batteryruntimecalculator.com/power-station-runtime-calculator) - [12V battery runtime12V deep-cycle runtime for RVs, vans and boats.](https://batteryruntimecalculator.com/12v-battery-runtime-calculator) - [mAh to Wh convertermAh to Wh for power banks, with the 100 Wh flight limit.](https://batteryruntimecalculator.com/mah-to-wh-calculator) - [Charge timeHours to charge from any state of charge, by charger amps.](https://batteryruntimecalculator.com/battery-charge-time-calculator) - [How runtime is calculatedThe formulas behind every calculator, with worked examples.](https://batteryruntimecalculator.com/how-battery-runtime-is-calculated)