Power Banks You Can Actually Fly With (100Wh Rule)

Every power bank in a carry-on is governed by one number, and it is not the one printed largest on the box. Airlines do not care about milliamp-hours. They care about watt-hours — and the limit is 100.

The good news is that almost every power bank sold for laptops sits under it. The bad news is that nothing on the packaging tells you that in the units security actually uses, so people either guess or find out at the checkpoint.

Key Takeaways

• The number that matters is watt-hours, and the threshold is 100 Wh for carrying a spare battery without airline approval.
• Convert it yourself: milliamp-hours divided by 1,000, multiplied by 3.6, gives watt-hours.
• Power banks must fly in the cabin, never in checked baggage — they are spare batteries, and that rule has no exceptions.
• Every laptop-class bank below comes in under 100 Wh, which is why they are all boardable.

The rule, in plain terms

The FAA treats a power bank as a spare lithium battery. Three thresholds apply:

Rule of thumb: milliamp-hours ÷ 1,000 × 3.6 = watt-hours. A 20,000 mAh bank is about 72 Wh. A 25,000 mAh bank is about 90 Wh. A 27,650 mAh bank is about 99.5 Wh — just under the line, which is not an accident.

That last figure explains an oddity you may have noticed: laptop power banks cluster suspiciously close to 27,000 mAh and then stop. Manufacturers are building right up to the airline limit and no further, because a bank you cannot board with is a bank nobody buys.

The picks, and their watt-hours

Every bank in the table below is under the 100 Wh threshold, so all of them board without approval. What separates them is output, not legality.

Best overall for a laptop: Anker 737

The one to carry if the laptop has to charge as fast as it does at a desk. High wattage in both directions, and a display that tells you what it is actually doing rather than four ambiguous dots.

Highest capacity that still boards: Anker Prime 27,650

The interesting one. At roughly 99.5 Wh it is as large as a power bank can legally be without airline approval — deliberately engineered against the ceiling. If you want maximum runtime per trip, this is the physical limit.

Best value: INIU 100W

Laptop-capable charging at a fraction of the flagship price. The compromise is charge speed into the bank itself and build finish, neither of which matters much on a three-day trip.

Slimmest for a laptop bag: Baseus Blade

Flat rather than cylindrical, which is the difference between a bank that slides into a laptop sleeve and one that does not. Lower capacity than the others, and correspondingly the lightest.

What people get wrong

What actually matters:

• Watt-hours, because that is the boarding rule
• Output wattage, because a laptop needs meaningfully more than a phone
• Whether it can charge and discharge at once, for overnight in a hotel
• Cabin-only packing, every single time

What matters less than the box implies:

• Milliamp-hours as a headline, since it is the wrong unit for both airlines and laptops
• Port count beyond two or three
• Fast-recharge claims, which describe refilling the bank rather than your laptop

Why checked baggage is a hard no

A spare lithium battery in the hold is unreachable if it fails. The prohibition exists because a fire in the cabin can be dealt with and a fire in the hold largely cannot. This applies to every power bank regardless of capacity, including small phone-sized ones.

What happens if you are over the line

Between 101 and 160 Wh you need the airline's approval in advance and you are limited to two spares. Above 160 Wh a power bank cannot travel in passenger baggage at all. In practice, consumer power banks above 160 Wh are rare precisely because they would be unsellable to travellers.

Airlines are tightening in-flight use

Several carriers have moved to restrict using or charging power banks during flight, and to require them to be visible rather than in an overhead bin. The capacity rules are the regulator's; the usage rules are increasingly the airline's, so it is worth a glance at your carrier's page before a long-haul.

How do I know my power bank's watt-hours?

Many banks print Wh on the casing in small text near the model number. If yours does not, divide the milliamp-hour rating by 1,000 and multiply by 3.6 — the nominal cell voltage manufacturers rate to. A 20,000 mAh bank works out around 72 Wh, comfortably inside the limit.

Can I bring more than one power bank?

Under 100 Wh each, yes — the FAA rule for that tier does not cap the number of spares for personal use, though individual airlines may. Between 101 and 160 Wh you are limited to two and need approval first.

Can a power bank go in checked luggage if the flight is short?

No. Length of flight makes no difference. Spare lithium batteries, including every power bank, must travel in the cabin.

Sources

• FAA PackSafe — Lithium batteries, spare or uninstalled (100 Wh threshold; 101-160 Wh requires airline approval, limit two; carry-on only)
• TSA — Portable chargers or power banks (permitted in carry-on, prohibited in checked bags)
• IATA — Lithium battery guidance for passengers (watt-hour classification used by carriers)