kWh to Amp-Hours Calculator
Convert energy in kilowatt-hours to battery capacity in amp-hours. Enter the kWh and nominal battery voltage; no time value is needed.
Quick answerAt 12 V, 1 kWh equals 83.33 Ah. At the 12.8 V nominal rating common on LiFePO4 batteries, it equals 78.13 Ah; at 24 V it is 41.67 Ah and at 48 V it is 20.83 Ah.
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Ideal electrical equivalence before reserve capacity and conversion losses.
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How it works
Amp-hours (Ah) = kilowatt-hours (kWh) × 1,000 ÷ volts. One kWh is 1,000 Wh, and watt-hours divided by volts gives amp-hours. Unlike converting kWh to amps, this capacity conversion does not need a time period.
kWh to amp-hours conversion chart
Battery voltage changes the amp-hour equivalent. The table uses Ah = kWh × 1,000 ÷ volts and includes the 12.8 V nominal rating common on LiFePO4 batteries.
| Energy | At 12 V | At 12.8 V | At 24 V | At 48 V |
|---|---|---|---|---|
| 0.5 kWh | 41.7 Ah | 39.1 Ah | 20.8 Ah | 10.4 Ah |
| 1 kWh | 83.3 Ah | 78.1 Ah | 41.7 Ah | 20.8 Ah |
| 2 kWh | 166.7 Ah | 156.3 Ah | 83.3 Ah | 41.7 Ah |
| 5 kWh | 416.7 Ah | 390.6 Ah | 208.3 Ah | 104.2 Ah |
| 10 kWh | 833.3 Ah | 781.3 Ah | 416.7 Ah | 208.3 Ah |
These are ideal capacity equivalents. A real battery bank needs extra capacity for usable-depth limits, inverter losses, temperature and aging.
Worked example: 1 kWh at 12 volts
One kWh equals 1,000 Wh. Divide 1,000 Wh by 12 V to get 83.33 Ah. At 24 V, the same energy is 41.67 Ah; at 48 V it is 20.83 Ah. Higher voltage means fewer amp-hours for the same stored energy.
Use the nominal system voltage shown on the battery or bank. A battery’s measured voltage changes with state of charge, so the live multimeter reading is not usually the right value for a nameplate-capacity comparison.
Battery sizing needs a safety margin
The result is an ideal unit conversion, not a complete battery-bank design. If the load needs 1 kWh, the battery must store more than 1 kWh whenever only part of its rated capacity is usable or an inverter and wiring introduce losses.
For a real design, divide the ideal Ah by the usable-capacity fraction and by system efficiency. Follow the battery and inverter manufacturers’ limits for current, wiring, fusing and compatible voltages.
Amp-hours are not amps
Amp-hours measure electric charge capacity. Amps measure current at a moment. Converting kWh to Ah requires voltage but not time; converting kWh to average amps requires both voltage and a time period. Use the related kWh-to-amps calculator when the question is current draw rather than battery capacity.
What a 12 V 100 Ah battery label means
A nominal 12 V, 100 Ah battery is 12 × 100 = 1,200 Wh, or 1.2 kWh of rated energy. A LiFePO4 battery labelled 12.8 V and 100 Ah is 1,280 Wh, or 1.28 kWh. That nameplate energy is not a promise of usable AC output. Battery-management limits, reserve depth, temperature, age, wiring and inverter losses can all reduce what reaches the load. Compare the calculator result with the exact manufacturer label and installation limits.
Frequently asked questions
How many amp-hours is 1 kWh at 12 V?
About 83.3 Ah: 1,000 Wh ÷ 12 V = 83.3 Ah. This is the ideal unit conversion before battery reserve and system losses.
How many amp-hours is 1 kWh at 24 V or 48 V?
At 24 V, 1 kWh is about 41.7 Ah. At 48 V, it is about 20.8 Ah.
Do I need hours to convert kWh to Ah?
No. Both kWh and Ah describe quantities accumulated over time. You only need voltage. A time value is required when converting kWh to average amps.
Can I size a battery directly from this answer?
Use it as a starting point only. Allow for the battery’s usable-depth limit, inverter efficiency, temperature, aging and the manufacturer’s current and installation limits.
How many kWh is a 12 V 100 Ah battery?
At a nominal 12 V, 100 Ah equals 1.2 kWh of rated energy. A battery labelled 12.8 V and 100 Ah equals 1.28 kWh. Usable output can be lower after reserve limits and conversion losses.
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