Can you take a power bank on a plane? The 100 Wh rule, hand luggage only
The label says 20,000 mAh, the airline website talks about watt-hours, and the security queue is in an hour. Here's how to tell, in under a minute, whether your power bank can fly.
Work out the watt-hours
The label should show a capacity in mAh and a battery voltage (usually 3.6 V or 3.7 V, the voltage of the cells inside, not the 5 V USB output). Multiply and divide by 1000. Many banks print the Wh figure directly, which is the number security staff look for.
| Label (mAh at 3.7 V) | Watt-hours | Can it fly? |
|---|---|---|
| 5,000 mAh | 18.5 Wh | Yes, hand luggage |
| 10,000 mAh | 37 Wh | Yes, hand luggage |
| 20,000 mAh | 74 Wh | Yes, hand luggage |
| 26,800 mAh | 99 Wh | Yes, just under the limit |
| 30,000 mAh | 111 Wh | Only with airline approval |
| 50,000 mAh | 185 Wh | No |
The power bank calculator does this for any label and shows the flight verdict next to how many phone charges you'll really get.
Why hand luggage and not the hold?
Lithium-ion cells can overheat and catch fire if they're damaged or short-circuited. In the cabin, crew can see and deal with it quickly; in the hold, nobody can. That's why the rule is the opposite of liquids: batteries stay with you. If a gate agent takes your cabin bag to the hold, take the power bank (and any spare batteries) out first.
Packing it safely
- Keep it in a pocket or a bag you can reach, not loose with keys or coins that could touch the ports.
- Don't fly with a bank that is swollen, cracked, has been dropped hard, or gets hot when idle.
- Pick one with a clear capacity label. Banks with no readable rating can be refused at security because staff can't check the Wh.
- Some countries add their own rules. For example, flights within China have required a visible certification mark on power banks since 2025.
Can you use it during the flight?
Carrying is one rule; using is another. Since 2025 a growing number of airlines either don't allow power banks to be used or charged on board at all, or ask that they stay visible rather than in the overhead locker. The rules change often and differ by airline, so check your airline's page on the day. Charge your phone from the seat USB port if there is one, or top up before boarding.
How many can you take?
Under 100 Wh there's usually no fixed number for personal use, though airlines can set their own limits and some cap spare batteries at around 20. For 100–160 Wh it's normally two, with approval. Bring what you need for the trip, not a crate.
Related
eSIM vs SIM for travel · Battery health %: when to replace · Phone battery drains overnight · Power bank mAh vs Wh · Why phones drain fast when travelling · Power bank calculator
Words explained on Wirebook: watt-hour · mAh · lithium-ion battery
Questions
Can I put a power bank in checked luggage?
No. Power banks are spare lithium batteries and must travel in hand luggage on passenger flights. If your cabin bag is moved to the hold at the gate, take the power bank out first.
Is a 20,000 mAh power bank allowed on a plane?
Yes. At 3.7 V it is about 74 Wh, under the 100 Wh limit, so it can go in hand luggage without airline approval.
What is the biggest power bank I can take on a plane?
Up to 100 Wh needs no approval, which is roughly 27,000 mAh at 3.7 V. Between 100 and 160 Wh you need the airline's approval, and above 160 Wh is not allowed.
How do I convert mAh to Wh?
Multiply the mAh by the battery voltage (usually 3.6 or 3.7 V) and divide by 1000. 10,000 mAh at 3.7 V is 37 Wh.
Can I use my power bank during the flight?
It depends on the airline. Since 2025 many airlines ban using or charging power banks on board or require them to stay visible, so check your airline's rules before you fly.
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