Free power bank calculators

What does a watt-hour
really cost?

mAh figures at different voltages, rated capacities and multi-packs make power banks hard to compare. Three small tools put them on equal terms.

Compare power bank prices Free to use. No sign-up. The maths is always shown.
01

Capacity & flights

mAh to Wh calculator

Enter the capacity printed on the power bank and the voltage it is rated at: see its energy in watt-hours and what the usual airline rules say about it.

02

Phone charges

Power bank phone charges calculator

Enter the power bank's capacity, your phone's battery and how much energy survives the trip: see how many full charges to expect.

03

Price per Wh

Power bank cost per Wh calculator

Turn the price on the box into the price of energy: enter what you pay, the capacity in mAh or Wh, and how many come in the pack.

Put the numbers to work

Find the cheapest watt-hour.

Our catalog ranks Amazon power banks and power stations by price per 100 Wh of battery energy.

Compare power bank prices
Free power bank calculators: mAh to Wh, phone charges, cost per Wh — Power Bank Price