Ah / Wh / kWh energy converter
Convert between amp-hours, watt-hours and kilowatt-hours at any voltage. Type in any field to convert.
Related tools
Quick reference
| Ah | At 12V (Wh) | At 24V (Wh) | At 48V (Wh) |
|---|---|---|---|
| 50 Ah | 600 Wh | 1,200 Wh | 2,400 Wh |
| 100 Ah | 1,200 Wh | 2,400 Wh | 4,800 Wh |
| 200 Ah | 2,400 Wh | 4,800 Wh | 9,600 Wh |
| 300 Ah | 3,600 Wh | 7,200 Wh | 14,400 Wh |
| 400 Ah | 4,800 Wh | 9,600 Wh | 19,200 Wh |
Ah vs Wh vs kWh — what's the difference?
Amp-hours (Ah) measure electric charge — how many amps flow for how many hours. A 100Ah battery can supply 10A for 10 hours (in theory). Ah is voltage-dependent: the same Ah at a higher voltage holds more energy.
Watt-hours (Wh) measure energy directly, independent of voltage. Wh = Ah × Voltage. This is the most useful unit for comparing batteries at different voltages or calculating whether your solar can power your loads.
Kilowatt-hours (kWh) are just 1,000 Wh — the same unit used for household electricity bills. A 100Ah 12V battery holds 1.2 kWh.
Wh = Ah × V | kWh = Wh ÷ 1000 | Ah = Wh ÷ V
Frequently asked questions
Why does voltage matter when comparing batteries?
Two 100Ah batteries at different voltages hold different amounts of energy. A 100Ah 12V battery holds 1.2 kWh; a 100Ah 24V battery holds 2.4 kWh — twice as much energy for the same Ah rating. Always compare batteries in Wh or kWh, not just Ah.
How do I convert my solar panel output to Ah?
Solar panels are rated in watts (W) and produce watt-hours (Wh) based on sun hours. To convert to Ah at your system voltage: Ah = Wh ÷ Voltage. A 200W panel producing 800 Wh in 4 peak sun hours gives 800 ÷ 12 = 66.7 Ah at 12V.
My battery is rated in Wh, not Ah — how do I compare it?
Divide the Wh rating by your system voltage to get Ah. A 1,500 Wh lithium battery on a 12V system is equivalent to 125 Ah. Many modern lithium batteries are sold by Wh because it's a more honest energy comparison across different voltages.