Ah to Wh Calculator
Enter amp-hours and battery voltage below — the watt-hours update instantly.
How do you convert Ah to Wh?
Multiply amp-hours by voltage: Wh = Ah × V. A 100 Ah battery at 12 V stores 100 × 12 = 1,200 Wh (1.2 kWh). Always use the battery's nominal voltage — a 100 Ah bank at 48 V holds four times the energy of the same 100 Ah at 12 V, because watt-hours scale directly with voltage.
Ah to Wh Formula
Amp-hours measure electric charge; watt-hours measure energy. Since energy = charge × voltage, multiplying capacity in Ah by the battery voltage gives the stored energy in Wh. This is why two batteries with the same Ah rating hold different energy if their voltages differ.
Ah to Wh at Common Battery Voltages
| Capacity | at 3.7 V | at 12 V | at 48 V |
|---|---|---|---|
| 2 Ah | 7.4 Wh | 24 Wh | 96 Wh |
| 5 Ah | 18.5 Wh | 60 Wh | 240 Wh |
| 10 Ah | 37 Wh | 120 Wh | 480 Wh |
| 50 Ah | 185 Wh | 600 Wh | 2,400 Wh |
| 100 Ah | 370 Wh | 1,200 Wh | 4,800 Wh |
| 200 Ah | 740 Wh | 2,400 Wh | 9,600 Wh |
Battery Capacity Across Different Chemistries
Because different batteries operate at different voltages, you can't compare their Amp-hour (Ah) ratings directly. Converting to Watt-hours (Wh) gives you a level playing field for total energy storage. Here are common real-world packs:
| Battery Type | Rated Capacity | Nominal Voltage | Total Energy (Wh) |
|---|---|---|---|
| RV / Marine Deep Cycle | 100 Ah | 12 V (Lead-Acid/LFP) | 1,200 Wh (1.2 kWh) |
| Golf Cart Battery | 225 Ah | 6 V (Lead-Acid) | 1,350 Wh (1.35 kWh) |
| E-Bike Battery | 15 Ah | 48 V (Li-ion) | 720 Wh |
| Cordless Tool Pack | 5 Ah | 18 V (Li-ion) | 90 Wh |
Always use the nominal voltage for capacity calculations. Li-ion e-bike packs labeled "54.6V" are often just 48V nominal packs showing their peak charging voltage.
Frequently Asked Questions
How do I convert Ah to Wh?
Multiply amp-hours by voltage: Wh = Ah × V. A 100 Ah battery at 12 V stores 100 × 12 = 1,200 Wh. Always use the battery's nominal voltage.
How many watt-hours is a 100Ah 12V battery?
100 Ah × 12 V = 1,200 Wh (1.2 kWh). At 24 V it would be 2,400 Wh; at 48 V, 4,800 Wh — the energy scales with voltage.
Which voltage should I use for the conversion?
Use the nominal voltage — 3.7 V for a Li-ion cell, 12 V for lead-acid, 48 V for a solar bank. It represents the average voltage across a discharge, which the preset buttons above fill for you.
What is the difference between Ah and Wh?
Ah measures charge and ignores voltage; Wh measures energy and includes it. Because Wh = Ah × V, watt-hours are the fairer way to compare batteries of different voltages.
Why do airlines care about Wh instead of Ah?
Amp-hours only tell you the charge, not the energy. A 10 Ah battery at 5V holds 50 Wh, but a 10 Ah battery at 48V holds 480 Wh (a massive fire risk). Airlines use Wh (typically capped at 100 Wh) because it represents the true explosive energy potential of the pack.