100 Wh to mAh
100 Wh is about 27,027 mAh at 3.7 V. At 12 V, it is about 8,333 mAh. The energy stays at 100 Wh; the equivalent charge capacity changes with voltage.
100 Wh at 3.7 volts equals 27,027 mAh.
100 Wh at 3.7 V
Equivalent charge capacity at this voltage
100 ÷ 3.7 × 1,000 = 27,027 mAh
- mAh
- 27,027
- Ah
- 27.027
- Wh
- 100
- kWh
- 0.1
These values describe the same battery rating at 3.7 V. We round the displayed values but keep the full result when you reverse the conversion.
A 10,000 mAh rating at 3.7 V is 37 Wh. At 7.4 V, the same charge capacity is 74 Wh. Check the battery label before changing the voltage.
Compare two battery labelsUse watt-hours to compare batteries at different voltages.
Understand the conversion
Why 100 Wh has more than one mAh equivalent
To convert Wh to mAh, divide by nominal voltage and multiply by 1,000. A higher voltage gives a smaller mAh number for the same energy. The energy stays the same.
A 100 Wh battery at 3.7 V and a 100 Wh battery at 12 V have the same nominal energy rating. Their charge capacities differ, and their voltage, current limits, and connectors determine which devices they can power.
At 5 V, 100 Wh corresponds to 20,000 mAh before conversion losses. Actual USB output capacity will be lower because converting voltage uses some energy.
Formula and worked example
mAh = 100 ÷ V × 1,000
At 3.7 V: mAh = 100 ÷ 3.7 × 1,000 ≈ 27,027
100 Wh ÷ 12.8 V × 1,000 = 7,812.5 mAh, or 7.8125 Ah.
The NIST conversion reference lists ampere-hours under electric charge and watt-hours under energy. The battery calculations here use nominal label voltage.
100 Wh converted to mAh by voltage
The energy remains 100 Wh in every row. Use the nominal voltage associated with your battery rating. This reference table stays fixed while you edit the calculator.
| Wh | Nominal voltage | mAh |
|---|---|---|
| 100 | 3.2 V | 31,250 |
| 100 | 3.7 V | 27,027 |
| 100 | 3.85 V | 25,974 |
| 100 | 5 V | 20,000 |
| 100 | 7.4 V | 13,513.5 |
| 100 | 12 V | 8,333.33 |
| 100 | 12.8 V | 7,812.5 |
| 100 | 24 V | 4,166.67 |
| 100 | 48 V | 2,083.33 |
Common questions
Is 100 Wh the same as 20,000 mAh?
They are equivalent at 5 V before losses. At 3.7 V, 100 Wh is about 27,027 mAh. A 20,000 mAh rating at 3.7 V is 74 Wh.
Why does a higher voltage give fewer mAh?
The relationship is Wh = Ah × V. When Wh stays fixed and voltage increases, Ah must decrease. Multiply Ah by 1,000 to express that charge capacity in mAh.
Can I compare batteries using only mAh?
Only comparing mAh can be misleading when voltages differ. Compare Wh for nominal energy, then check whether each battery meets the device's electrical requirements.