# Power Bank Capacity and Flight Rules Calculator

Work out how big a power bank you need for your devices, how long it takes to charge, and whether it is allowed on a plane.

- URL: https://toolstackhub.co.uk/tools/power-bank-capacity-calculator/
- Category: Calculators
- Price: free, no sign-up
- Privacy: runs in the browser; input is not uploaded
- Last updated: 2026-10-08

## About
Enter the battery size of your phone, tablet or laptop and how many full charges you want. The calculator allows for conversion losses, tells you the capacity to look for in mAh and watt-hours, estimates charging time from the wattages involved, and checks the common airline limits: power banks up to 100 Wh are normally allowed in cabin baggage and 100 to 160 Wh usually need airline approval. Airline rules vary, so check yours.

## How to use
1. Enter your values in the fields above.
2. The result updates automatically as you type.
3. Copy or note the figures you need.

## FAQ
**Why does a 20,000 mAh power bank not charge my 5,000 mAh phone four times?** Capacity is quoted at the cell voltage, and energy is lost as heat during conversion. With typical 65 to 75% efficiency you get about three charges.

**What are the airline limits?** Most airlines allow power banks up to 100 Wh in cabin baggage, 100 to 160 Wh with airline approval, and none above 160 Wh. They must be in cabin baggage, not checked baggage. Rules differ by airline.

**Is the Power Bank Capacity and Flight Rules Calculator free?** Yes, with no sign-up or limits.