Every airline on earth uses the same number, and almost nobody knows how to check it. Here is the ten-second version.
The rule is simpler than the confusion around it suggests. Lithium battery packs are allowed on commercial flights only in carry-on baggage, and only up to 100 watt-hours (Wh) per battery. Above that, you need airline approval. Above 160 Wh, you cannot fly with it at all.
Two things trip people up. First, power banks are advertised in mAh, and the limit is written in Wh — different units. Second, the "carry-on only" part is not a suggestion. A battery in the hold is unreachable if it fails; a battery under your seat is not.
Converting mAh to Wh
The formula is one line:
So a 10,000 mAh bank is (10 × 3.7) = 37 Wh. A 5,000 mAh bank is 18.5 Wh. Both sit far under the 100 Wh ceiling, which is why the vast majority of consumer power banks are cleared without a conversation.
| Rated capacity | Watt-hours | Flight status |
|---|---|---|
| 5,000 mAh | 18.5 Wh | Carry-on, no approval needed |
| 10,000 mAh | 37 Wh | Carry-on, no approval needed |
| 20,000 mAh | 74 Wh | Carry-on, no approval needed |
| 27,000 mAh | 99.9 Wh | Right at the ceiling |
| 30,000 mAh | 111 Wh | Airline approval required |
Figures assume 3.7 V nominal cells. Check the printed Wh rating on your device where available.
What airlines actually check
Most crews are looking for a printed rating on the housing. Reputable manufacturers etch or print the Wh value directly on the shell precisely so this takes seconds at the gate. If your bank has no marking at all, expect more questions — an unlabelled cell pack is the one that gets pulled.
A few practical habits that keep this uneventful:
- Keep it in your personal item, not the overhead bin, and never in checked luggage.
- Cover exposed terminals. Loose banks rattling against keys and coins are the actual fire risk, not the battery sitting quietly in a pocket.
- One bank per person is uncontroversial. Carrying several spares can trigger the "spare batteries" limits that vary by carrier.
- Newer rules restrict in-flight use. Several Asian and Middle Eastern carriers now ban charging from a power bank during the flight and require it to stay visible rather than in the overhead bin. Check your specific airline before you fly.
Why smaller is often smarter for travel
There is a real trade-off hiding in the capacity race. A 30,000 mAh brick needs airline sign-off, weighs over half a kilo, and takes most of a day to refill. A 5,000 mAh magnetic bank is 120 g, clears every checkpoint without discussion, and covers the gap between a morning flight and an evening hotel — which is the actual job most travellers need done.
If you are choosing for travel specifically, weight and hassle usually beat headline capacity. The bank you actually carry is worth more than the one you left at home because it was heavy.
Common questions
Can a power bank go in checked luggage?
No. Lithium-ion batteries must travel in the cabin on every major airline, because a fault in the hold cannot be reached or extinguished by the crew.
Is 10,000 mAh allowed on a plane?
Yes. At 3.7 V it works out to 37 Wh, comfortably under the 100 Wh limit, and needs no special approval.
How many power banks can I bring?
Rules vary, but two spare batteries per passenger is the common allowance for units between 100 and 160 Wh. Under 100 Wh, most carriers are relaxed about a personal quantity.
Do magnetic power banks cause problems at security?
No. The magnets used for wireless alignment are small and shielded, and pose no issue for aircraft systems or screening equipment.