Power Bank Charges Calculator
Fill in the values and the answer updates as you type.
How the Power Bank Charges Calculator works
Power banks list capacity at the cell voltage (3.7 V) but deliver power at 5 V or more, so only 60–80% of the rating reaches your phone. Charges = rating × efficiency ÷ phone battery capacity. A lower efficiency figure is safer for cheap power banks. Example: with the default values, full phone charges comes to 3.1.
Inputs and results
The Power Bank Charges Calculator takes 3 inputs and gives 3 results.
What you enter
- Power bank rating (mAh) — starts at 20000.
- Phone battery (mAh) — starts at 4500.
- Conversion efficiency (%) — starts at 70.
What you get
- Full phone charges
- Usable power bank capacity (mAh)
- Whole charges
Example: Power Bank Charges Calculator with the starting values
With power bank rating 20000 mAh, phone battery 4500 mAh and conversion efficiency 70 %, the calculator returns:
| Full phone charges | 3.1 |
|---|---|
| Usable power bank capacity (mAh) | 14,000 |
| Whole charges | 3 |
Change any value above and the results update straight away.
Power Bank Charges Calculator FAQ
How do I use the Power Bank Charges Calculator?
Enter power bank rating, phone battery and conversion efficiency in the fields, then read full phone charges, usable power bank capacity (mah) and whole charges in the result panel. The answer updates as you type, and you can press Calculate or Enter to refresh it. Use “Copy link” to share your exact numbers with someone else.
What does the Power Bank Charges Calculator calculate?
How many times a power bank can charge your phone. It returns full phone charges, usable power bank capacity (mah) and whole charges from the 3 values you provide.
What values does the Power Bank Charges Calculator start with?
It opens with power bank rating 20000 mAh, phone battery 4500 mAh and conversion efficiency 70 % so you can see a working result straight away. Replace them with your own numbers, or press Reset to return to these starting values.
Is the Power Bank Charges Calculator free and private?
Yes. It is free, needs no account, and runs in your browser, so nothing you type is sent to or stored on our servers. See the Privacy Policy for details.
Can I rely on the Power Bank Charges Calculator for important decisions?
Treat the result as a well-rounded estimate. Real situations often have details a general calculator cannot know, so confirm important decisions with a qualified professional. See the Disclaimer for more.