Electronics calculator
What Power Bank Size Do I Need?
Enter device battery energy wh, desired full recharges, and conversion efficiency to work out power-bank minimum energy.
Enter your measurements
The key to what power bank size do i need is having the right measurements: device battery energy wh, desired full recharges, and conversion efficiency. This minimum-capacity calculation uses them to return power-bank minimum energy in a form you can compare directly.
- Device battery energy Wh — Required
- Desired full recharges — Required
- Conversion efficiency — Required
Power-bank minimum energy
Enter the measurements above to calculate power-bank minimum energy.
How the calculation works
Method: requiredWh=deviceBatteryWh×recharges/conversionEfficiency. This is the exact rule used to generate power-bank minimum energy for this page.
Worked example
Example: Device battery energy Wh = 60 Wh; Desired full recharges = 2; Conversion efficiency = 50%. Result: Required Wh = 240 Wh.
Before you decide
Use the finished, usable dimensions after trim, handles, skirting, packaging or other projections where relevant. This page calculates the stated geometry or quantity only; product-specific construction or installation details can still affect the final choice. For what power bank size do i need, the limiting result on this page is power-bank minimum energy.
Direct measurement/geometry calculation. No external reference is required for the arithmetic itself; the result is derived only from the user-entered measurements and the formula stored in calculationLogicJson.
Frequently asked questions
What does the Power Bank Size calculator tell me?
It returns power-bank minimum energy from the measurements entered on this page. The calculation is specific to power bank size, so the result should be compared with the exact product or specification you are considering.
Which measurements should I take for power bank size?
Measure device battery energy wh, desired full recharges, conversion efficiency. Use clear, usable dimensions rather than nominal room or product labels.
Should I round the power-bank minimum energy?
Keep the calculated value for comparison, then choose a real product that meets or stays within the returned power-bank minimum energy while allowing for the clearances, tolerances or ratings shown by its manufacturer.