Convert Milliamp-hours (mAh) to Watt-Hours (Wh)
Powerbanks are labelled in mAh, but airlines limit batteries in Wh. The conversion needs a voltage: Wh = mAh × V ÷ 1000, and this converter uses the Li-ion nominal 3.7 V — so 10,000 mAh = 37 Wh.
Formula
1 mAh = 0.0037 Wh
To convert mAh to Wh, divide the value by 270.27027.
Conversion Table
| Milliamp-hours (mAh) | Watt-Hours (Wh) |
|---|---|
| 100 mAh | 0.37 Wh |
| 200 mAh | 0.74 Wh |
| 500 mAh | 1.85 Wh |
| 1000 mAh | 3.7 Wh |
| 1500 mAh | 5.55 Wh |
| 2000 mAh | 7.4 Wh |
| 2500 mAh | 9.25 Wh |
| 3000 mAh | 11.1 Wh |
| 4000 mAh | 14.8 Wh |
| 5000 mAh | 18.5 Wh |
| 6000 mAh | 22.2 Wh |
| 8000 mAh | 29.6 Wh |
| 10000 mAh | 37 Wh |
| 15000 mAh | 55.5 Wh |
| 20000 mAh | 74 Wh |
| 26800 mAh | 99.16 Wh |
| 30000 mAh | 111 Wh |
| 40000 mAh | 148 Wh |
| 50000 mAh | 185 Wh |
| 100000 mAh | 370 Wh |
Common mAh to Wh Examples
- 1000 mAh = 3.7 Wh
- 2000 mAh = 7.4 Wh
- 3000 mAh = 11.1 Wh
- 5000 mAh = 18.5 Wh
- 10000 mAh = 37 Wh
- 20000 mAh = 74 Wh
- 26800 mAh = 99.16 Wh
- 30000 mAh = 111 Wh
About mAh to Wh
Powerbank capacities are quoted at the cell voltage of 3.7 V (not the 5 V USB output), which is why the industry rule is Wh = mAh × 3.7 ÷ 1000. A 20,000 mAh bank is 74 Wh, and the popular 26,800 mAh size is 99.2 Wh — deliberately just under the 100 Wh airline carry-on limit that applies without special approval (100–160 Wh usually needs airline approval; above 160 Wh is banned from passenger flights).
For a different chemistry the figure shifts a few percent — 3.2 V LiFePO4 cells or 3.85 V modern phone cells — so when precision matters, multiply mAh by the actual nominal voltage printed on the battery.
Frequently Asked Questions
Is a 20,000 mAh powerbank allowed on a plane?
Yes — 20,000 mAh × 3.7 V = 74 Wh, under the 100 Wh limit airlines apply to carry-on batteries. It must go in hand luggage, not checked bags.
Why is 3.7 V used for the conversion?
It is the nominal voltage of a Li-ion cell, and manufacturers rate powerbank mAh at cell voltage — not at the 5 V USB output.
How is mAh used in everyday life?
Milliamp-hours appears in measurements, product labels, and reports wherever the local convention favors that unit for Battery Capacity.
How is Wh used in everyday life?
Watt-Hours is commonly seen in regions and contexts where it is the preferred Battery Capacity unit, from signage to technical specifications.
What are common uses for converting mAh to Wh?
Typical scenarios include travel, trade, engineering, science, and any situation where data is reported in mAh but needed in Wh.
Which industries rely on mAh to Wh conversions?
Logistics, manufacturing, scientific research, and international commerce all routinely move between mAh and Wh.
How accurate is the mAh to Wh calculator?
The calculator uses the standard ratio 0.0037 and returns results to several decimal places, suitable for both casual and technical use.
Does temperature, humidity, or pressure affect mAh to Wh results?
No. The conversion factor between mAh and Wh is a fixed mathematical ratio and does not depend on environmental conditions.