Power Banks Fly Carry-On Only, Up to 100Wh Without Asking

Yes, you can take a power bank on a US flight, but only in your carry-on, and up to 100Wh it needs no one’s permission. Between 101 and 160Wh the FAA requires the airline’s approval, and Delta, American and Southwest cap power banks at 100Wh anyway; above 160Wh is forbidden on passenger planes.

How many you can take is now an airline question. Southwest allows one power bank per person, Delta, American and United allow two, and the FAA sets no count for packs under 100Wh.

The federal limits, by size

The FAA’s rules apply to every US flight, and TSA enforces the carry-on half at the checkpoint: power banks are “Carry On Bags: Yes, Checked Bags: No”.

Capacity	FAA rule	How many
Up to 100Wh	Allowed in the cabin, no approval needed	No limit, if for your own use
101–160Wh	Needs the airline’s approval	Two spares per person
Over 160Wh	Forbidden on passenger aircraft	None

Two FAA details catch people out. If your carry-on is checked at the gate or planeside, the power bank has to come out of it and stay with you in the cabin. And damaged or recalled batteries are not allowed in either cabin or hold unless they have been removed or made safe.

The FAA also wants the terminals protected from short circuit: retail packaging, tape over the contacts, or a snug plastic bag or protective pouch.

What four US airlines add

The FAA says many airlines have stricter quantity and watt-hour limits, and Southwest’s, American’s, Delta’s and United’s own pages bear that out.

Airline	How many	Largest	In the cabin
Southwest	One per person, since 20 April 2026	100Wh	Under the seat, not the overhead bin; visible when in use; no charging it from seat power
American	Two	100Wh each	Within reach and visible when in use; not in the overhead bin; no recharging from seat outlets
Delta	Two	100Wh each, “with no exceptions”	Not in the overhead bin; no recharging on board; not used to charge a device during taxi, take-off or landing
United	Two	Lists general limits: 100Wh, or up to two at 101–160Wh	On you or in your personal item; not in the overhead bin; no recharging from aircraft power

So at three of the four, the FAA’s 101–160Wh band does not exist for power banks: there is no approval to ask for. United’s page gives the general battery limits without a separate power-bank cap, and does not say whether a pack over 100Wh counts under them. If yours is that size, ask United before you fly rather than at the gate.

Southwest is the airline to plan around if you fly more than one. One power bank, at or under 100Wh, out of your bag while it is charging something.

Gaming handhelds are where the 100Wh line starts to bite. The ROG Ally X alone carries an 80Whr battery, which is why our piece on handheld battery life treats a 100Wh pack as roughly one full refill.

Reading the label

The FAA says newer lithium-ion batteries have the watt-hour rating printed on them, and American says it is usually on the back or base of the charger. If yours has one, that is the number to use, and you are done.

If it lists only milliamp-hours, the FAA’s formula is: divide the mAh by 1,000, then multiply by the voltage. American Airlines publishes the same thing with the voltage filled in, Wh = mAh × 3.7 ÷ 1,000, and gives a 10,000mAh charger as 37Wh.

Printed capacity	Watt-hours at 3.7V	Under FAA rules
5,000mAh	18.5Wh	Allowed
10,000mAh	37Wh	Allowed
20,000mAh	74Wh	Allowed
25,000mAh	92.5Wh	Allowed
26,800mAh	99.2Wh	Allowed, just
30,000mAh	111Wh	Airline approval; not on Delta, American or Southwest
40,000mAh	148Wh	Airline approval; not on Delta, American or Southwest

The table is our arithmetic on American’s formula. If your pack prints a voltage other than 3.7V beside its mAh figure, use that voltage instead: the FAA multiplies by the battery’s own volts, and a different voltage gives a different answer. If the label shows neither watt-hours nor a voltage, there is nothing reliable to work from, and United’s advice for a battery you are unsure about is not to pack it.

Before you pack

1. Find the watt-hours on the label, or work them out from mAh and the printed voltage.
2. Check your airline’s count. One on Southwest; two on Delta, American and United.
3. Put it in the bag that stays with you. If that bag is gate-checked, take the power bank out.
4. Leave a damaged or swollen one at home. The FAA bars damaged and recalled batteries from the cabin and the hold.
5. On board, keep it with you or under the seat in front, not in the overhead bin, and do not plan on recharging it from the seat power on any of these four airlines.

The phone you are charging deserves a glance too: a battery that drains fast on the ground drains fast in the air, and you can check its battery health in Settings before you leave. If the trip is abroad, the other phone questions are what your carrier charges per day overseas and whether your charger needs more than a plug adapter.

Questions people ask

Can I bring a power bank on a plane?

Yes, in your carry-on. The FAA and TSA both say power banks cannot go in checked bags. If your carry-on is checked at the gate, the FAA says to take the power bank out and keep it with you in the cabin.

What size power bank is allowed on a plane?

Up to 100Wh with no airline approval under FAA rules. 101 to 160Wh needs the airline’s approval, and Delta, American and Southwest cap power banks at 100Wh regardless. Above 160Wh is forbidden on passenger planes.

Is a 20000mAh power bank allowed on a plane?

At 3.7 volts, the figure American Airlines uses, 20,000mAh works out to 74Wh, under the 100Wh limit. Check the label: if it prints a watt-hour rating or a different voltage, that figure is the one that counts.

How do I convert mAh to Wh?

Divide the mAh by 1,000 and multiply by the battery’s voltage. That is the FAA’s formula. American Airlines publishes it as Wh = mAh × 3.7 ÷ 1,000, so a 10,000mAh pack is 37Wh.

How many power banks can I take on a plane?

It depends on the airline. Southwest allows one per person, and Delta, American and United allow two. The FAA itself sets no count under 100Wh for personal use, and two per person between 101 and 160Wh.

Can I use a power bank during the flight?

On the airlines we checked, yes, with conditions. Southwest and American say it must be visible while in use, Delta bars using one to charge a device during taxi, take-off and landing, and none of the four let you recharge it from the seat power.

Why can’t power banks go in checked luggage?

Asked why lithium-ion batteries belong in the cabin, the FAA says they can overheat into thermal runaway, sometimes without warning, and that flight crews are trained to recognise and respond to battery fires in the cabin.