Wh to mAh Calculator
A Wh to mAh calculator converts battery energy in watt-hours into battery capacity in milliamp-hours. This is useful when a battery, power bank, or laptop pack is labeled in Wh but you want to compare it with devices or cells commonly listed in mAh.
This calculator estimates equivalent mAh using the battery voltage you select. That matters because the same Wh value produces a different mAh number at different voltages.
Short answer: To convert Wh to mAh, divide watt-hours by voltage and multiply by 1000. The lower the voltage, the higher the mAh number for the same amount of energy.
Wh to mAh Converter
Convert battery energy in watt-hours to equivalent milliamp-hours using Li-ion, LiFePO4, LiPo, or custom voltage
Conversion Formula
The standard conversion formula is:
mAh = (Wh × 1000) ÷ Voltage
For example, 37 Wh at 3.7V becomes 37 × 1000 ÷ 3.7 = 10000 mAh. This is why many 10,000 mAh power banks are often around 37 Wh at the cell level.
Battery Voltage Guide
Li-ion
Li-ion batteries are commonly converted using 3.7V nominal voltage in consumer battery math.
LiFePO4
LiFePO4 batteries are commonly converted using 3.2V nominal voltage per cell.
LiPo
LiPo batteries are also commonly modeled around 3.7V nominal voltage per cell.
Why voltage matters
The same energy value in Wh converts to a larger mAh number at lower voltage and a smaller mAh number at higher voltage.
Common Wh to mAh Conversions
| Energy | Voltage | Equivalent Capacity |
|---|---|---|
| 10 Wh | 3.7V | 2703 mAh |
| 20 Wh | 3.7V | 5405 mAh |
| 37 Wh | 3.7V | 10000 mAh |
| 54 Wh | 3.7V | 14594 mAh |
| 100 Wh | 3.7V | 27027 mAh |
These numbers are correct when the voltage assumption is 3.7V. If the battery uses a different nominal voltage, the mAh result changes even though the energy in Wh stays the same.
How to Use It
Step 1
Enter the battery energy in Wh from the product label or datasheet.
Step 2
Select Li-ion, LiFePO4, LiPo, or enter the correct nominal voltage manually.
Step 3
Calculate the equivalent mAh and compare it with marketed battery or power bank capacities.
Step 4
Use the same nominal voltage on both products when making fair capacity comparisons.
Practical warning: Wh is the better way to compare energy across different voltages. mAh alone can be misleading if two batteries use different nominal voltages.
Worked Example
If you want to convert 50 Wh at 3.7V, the math is 50 × 1000 ÷ 3.7 = 13,513.5 mAh, which is commonly rounded to 13,514 mAh. That matches the FAQ example you provided.
Likewise, 100 Wh at 3.7V becomes 27,027 mAh. That is the same example often used when comparing travel-limit batteries and high-capacity portable power products.
Practical rule: Use Wh for the fairest battery comparison, and use mAh only after confirming the voltage basis is the same.