Your power bank says 20,000mAh. The airline’s rules say 100 watt-hours. Those are different units measuring different things, the label almost never shows the one the airline cares about, and in 2026 a fresh set of rules changed how you’re allowed to use a power bank in the air. No wonder people get pulled aside at security. Here is exactly what you can bring, how to translate the numbers, and what changed this year.
Power banks must go in your carry-on, never checked baggage. Up to 100Wh (about 27,000mAh) needs no approval — that covers almost every consumer power bank. From 101–160Wh you need airline permission (usually two units max). Over 160Wh is banned. New for 2026: many airlines now ban using or charging a power bank during the flight and want it kept in view, not in the overhead bin.
What’s allowed, at a glance
| Capacity (at 3.7V) | Watt-hours | Allowed? |
|---|---|---|
| 10,000mAh | ~37Wh | Yes — no approval |
| 20,000mAh | ~74Wh | Yes — no approval |
| 27,000mAh | ~100Wh | Yes — the ceiling |
| ~28,000–43,000mAh | 101–160Wh | Airline approval needed |
| Above ~43,000mAh | Over 160Wh | Not allowed |
Why airlines measure watt-hours, not mAh
mAh (milliamp-hours) only describes charge at a given voltage — it’s half of the story. Watt-hours (Wh) measure the actual energy stored, which is what determines fire risk, so that’s the number aviation rules use. To convert, use the cell voltage of a lithium battery, normally 3.7V:
Wh = (mAh ÷ 1000) × 3.7
So a 10,000mAh bank is about 37Wh, a 20,000mAh bank about 74Wh, and a 26,800–27,000mAh bank lands right around the 100Wh limit. Many power banks now print the Wh figure somewhere on the casing — if yours does, use that number and skip the math.
The rules that don’t change
Carry-on only. Power banks count as spare lithium batteries, and spare batteries are forbidden in checked luggage worldwide — a fire in the hold is far more dangerous than one in the cabin, where it can be dealt with. The 100Wh line is the one to remember: stay under it and you can carry several without asking anyone. 101–160Wh is the “ask first” zone — permitted with airline approval, typically limited to two spares. Above 160Wh (big station-style units) is simply not allowed on passenger flights.
What changed in 2026
After a run of in-cabin battery fires, the industry tightened how power banks may be used, not just carried. As of January 2026, IATA guidance discourages charging power banks from in-seat USB ports, and 20-plus airlines — including Emirates, Singapore Airlines, the Lufthansa Group and major Korean carriers — now prohibit actively using a power bank during the flight. Several also require it to be kept where you can see it (a seat pocket or under the seat), not buried in an overhead bin, so a problem is spotted fast. The capacity limits are unchanged; what’s new is the “don’t use it mid-flight” expectation. Always check your specific airline before you fly.
How to check your own power bank in 30 seconds
Look on the body of the unit for either a Wh rating (use it directly) or the mAh and voltage. If it shows 20,000mAh at 3.7V, that’s 74Wh — well under the limit. If a bank only lists a higher “output” voltage like 5V, don’t use that for the math; the airline cares about the cell energy at 3.7V, which is what the Wh label already reflects. When a unit shows no Wh and no clear voltage, assume the standard 3.7V conversion.
Practical tips for a hassle-free trip
Stick to a bank under 100Wh and you’ll never need a conversation at the gate — for most travelers a 20,000mAh (about 74Wh) unit is the sweet spot of capacity and zero paperwork. Keep it in your personal item, not the overhead bin. Don’t plan to charge devices from it during taxi, takeoff or the cruise if your airline bans in-flight use — charge up beforehand. And if you’re wondering why a big charger fills your phone slowly to begin with, that’s a different issue entirely, covered in our guide to PPS fast charging and what your USB-C cable can actually do.
Frequently asked questions
How many mAh power bank can I take on a plane?
Up to about 27,000mAh — that’s the equivalent of the 100 watt-hour limit at the standard 3.7V. Below that, you need no special approval and can carry more than one. Between roughly 28,000 and 43,000mAh (101–160Wh) you need airline permission, and anything larger is not allowed.
Why do airlines use watt-hours instead of mAh for power banks?
Because watt-hours measure the actual energy stored, which determines fire risk, while mAh only describes charge at a particular voltage. To convert, divide the mAh by 1000 and multiply by 3.7 (the cell voltage of a lithium battery). Many power banks also print the Wh figure on the casing.
Can a power bank go in checked luggage?
No. Power banks are treated as spare lithium batteries, which are banned from checked baggage on every airline because a fire in the cargo hold is far harder to control. They must travel in your carry-on or personal item.
Can you use a power bank during a flight in 2026?
Increasingly, no. As of 2026, more than 20 airlines — including Emirates, Singapore Airlines, the Lufthansa Group and major Korean carriers — ban actively using or charging a power bank in flight, and IATA discourages charging them from in-seat USB ports. Many also require the bank to be kept visible rather than in the overhead bin. Check your airline’s policy before flying.
Is a 20000mAh power bank allowed on a plane?
Yes, easily. A 20,000mAh power bank is about 74 watt-hours, comfortably under the 100Wh limit, so it’s allowed in carry-on baggage with no approval needed. Just don’t pack it in checked luggage, and avoid using it in flight if your airline prohibits that.