Estimated full-charge time
1h 2m
Uses effective average power, not peak adapter ratingHow this calculator helps
Estimate a full-charge duration from battery energy and effective charger power. A taper-and-loss allowance accounts for conversion losses and the slower final part of a normal charging curve.
How to use it
- 1
Enter battery capacity from the exact phone variant.
- 2
Use realistic effective charging watts, not only the charger's maximum label.
- 3
Apply a taper-and-loss allowance and compare with independent charging tests.
Formula and methodology
Battery energy ≈ capacity in Ah × 3.85 V. Charging time = battery energy ÷ charger watts × (1 + loss and taper allowance).
Worked calculation example
A 5,000 mAh battery stores about 19.25 Wh. At an effective 25 W and a 35% allowance, the idealised estimate is roughly one hour.
What can affect the result?
Charging protocol
The phone, cable and adapter must support the same fast-charging standard.
Thermal limits
Heat can cause the phone to reduce power substantially.
Charge range
Charging from 20% to 80% differs from a complete 0% to 100% cycle.
Limits of this estimate
The calculation uses nominal 3.85 V battery energy and constant effective power; real charging follows a variable curve controlled by the device.
Frequently asked questions
Is the mobile charging time calculator free?＋
Yes. SolvePilot tools are free, work in your browser, and require no account.
Does SolvePilot store my values?＋
No. Calculations run locally in your browser and the values you enter are not sent to a server.
Should I treat the result as an exact bill or quotation?＋
No. Results are informed estimates. Final charges can vary because of taxes, tariffs, lender terms, usage patterns, or provider rules.
How can I improve the accuracy?＋
Use recent values from your own bill, statement or institution, review every assumption, and confirm important results with the relevant official source.
Why is the advertised charger wattage not maintained?＋
Phones reduce power because of temperature, battery state, protocol limits and the charging taper near full.