Can I bring my power bank on a plane?
The FAA and TSA strictly regulate lithium-ion batteries on flights. The limit is based on Watt-hours (Wh), not milliamp-hours (mAh). Because most power banks only advertise mAh, this calculator does the conversion for you.
The Flight Rules:
- Under 100Wh: Allowed in carry-on bags without airline approval. (Usually any power bank under 26,800mAh).
- 101Wh - 160Wh: Allowed in carry-on bags, but requires airline approval before boarding.
- Over 160Wh: Strictly prohibited on passenger flights.
- Checked Bags: ALL power banks are prohibited in checked luggage due to fire risk.
Why don't I get the full mAh?
A 20,000mAh power bank cannot fully charge a 5,000mAh phone 4 times. Power banks store energy at ~3.7V, but USB outputs at 5V, 9V, or 12V. This conversion process, plus heat generated during charging, loses roughly 25–35% of the stored energy.
Our calculator uses a 70% real-world efficiency and your device's battery energy in watt-hours, so a 20,000 mAh bank shows about 2.7 charges for a 5,000 mAh phone.
Frequently asked questions
Can I bring a power bank on a plane in the US?
Yes, but only in carry-on bags, never in checked luggage. The TSA and FAA allow lithium batteries up to 100 watt-hours without airline approval. Batteries from 101 to 160 Wh need airline approval and are limited to two per passenger. Batteries over 160 Wh are prohibited.
How do I convert mAh to watt-hours?
Multiply the capacity in mAh by the cell voltage (usually 3.6 or 3.7 V) and divide by 1,000. A 20,000 mAh power bank at 3.7 V is 74 Wh, well under the 100 Wh limit. A 27,000 mAh bank is about 99.9 Wh.
How many phone charges will I get from a power bank?
Real-world efficiency is around 60% to 70% because of voltage conversion and heat. A 10,000 mAh power bank typically delivers about 6,000 to 7,000 mAh to a phone, roughly 1.5 charges for a phone with a 4,500 mAh battery.
What power bank size is best for travel?
A 10,000 mAh bank is pocket-sized and covers a day of heavy use. A 20,000 mAh bank with 45 W or higher USB-C PD output can also top up a tablet or small laptop and still fits airline limits.