Power bank buying guide: mAh, watts and airline rules explained
How to pick the right size without paying for capacity you'll never use.
SmartFinds TeamSmartFinds editors
7 min read
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Power banks are sold on big mAh numbers, but capacity is only half the story. Here is how to pick the right one for your phone, tablet or laptop.
Capacity (mAh)
A 10,000 mAh bank charges most phones about twice. 20,000 mAh covers a weekend away or a tablet. Expect to get around 60–70% of the rated capacity in real use.
Output (watts)
- 20W USB-C PD is enough for fast phone charging
- 45–65W is needed for most laptops
- Check that the port, not just the bank, supports the wattage
Airline rules
Most airlines allow power banks up to 100Wh (about 27,000 mAh) in carry-on luggage only. Never pack one in checked bags.
Our advice
Buy the smallest bank that covers your longest normal day, plus one extra charge.
SmartFinds Team
