Power bank watt-hours

Watt-hours, abbreviated Wh, measure the total energy a battery can store, and airlines use this number specifically to decide what power banks are allowed on a flight. Most power banks list their capacity in milliamp hours, or mAh, on the packaging, but airline rules are written in watt-hours, so the two numbers need to be converted to check a device against the rules.

As a general guide, power banks up to 100 Wh are typically allowed in carry-on luggage without special permission, banks between 100 and 160 Wh often need airline approval in advance, and anything above 160 Wh is usually not allowed on passenger flights at all. Power banks of any size are not allowed in checked luggage on most airlines, only in carry-on bags in the cabin.

To check a specific power bank, look for the Wh rating printed on the device itself, or convert the mAh and voltage shown into watt-hours using the standard formula. A common mistake is assuming a power bank is fine because it looks similar in size to one used before, or packing one in checked luggage because the carry-on was already full, both of which can lead to it being confiscated at security.