100 watt-hours equals 27,027 mAh at 3.7 V or exactly 20,000 mAh at 5 V — the airline carry-on battery limit explained.
| Input | Result |
|---|---|
| 100 Wh at 3.7 V | 27,027 mAh |
| 100 Wh at 5 V | 20,000 mAh |
| 100 Wh at 12 V | 8,333 mAh |
At 3.7 V: 27,027 mAh. At 5 V: exactly 20,000 mAh. The answer depends on the voltage because mAh is charge, not energy — Wh is the real energy measure.
Yes — 100 Wh is the IATA carry-on threshold: batteries up to 100 Wh need no approval, 100–160 Wh need airline approval, above 160 Wh is forbidden. A 20,000 mAh / 5 V power bank sits exactly at the limit.
A 20,000 mAh bank rated at 5 V output equals 100 Wh. Rated at 3.7 V cell voltage, the same bank is only 74 Wh — which is why many airlines accept it. Check the Wh figure printed on the case first.