EV Charging Time Calculator
Estimate how long it takes to charge an electric car from your battery size, charger power, start and target charge, and charging efficiency.
How it works
Energy = capacity × (target% − start%) · Time = energy ÷ (charger power × efficiency%)
The energy you add is the battery capacity times the percentage you fill. Dividing that by the charger’s effective power — its rated power scaled by charging efficiency — gives the time in hours, which is shown here as hours and minutes. Efficiency matters because some of the power drawn from the wall is lost to heat and the onboard charger rather than reaching the cells, so a lower efficiency stretches the time. This is a flat-rate estimate: in practice charging speed tapers as the pack fills (fast chargers slow sharply past 80%), and cold weather slows it further, so real sessions usually run a little longer than this.
Worked example
A 60 kWh battery charged from 20% to 80% needs 36 kWh. On a 7.4 kW wallbox at 90% efficiency the effective rate is 6.66 kW, so the top-up takes about 36 ÷ 6.66 ≈ 5.4 hours, or roughly 5h 24m.
Frequently asked questions
Why does charging slow down near 100%?
To protect the battery, the car reduces the charging current as the pack approaches full — most noticeably on DC fast chargers above 80%. This tool uses a constant rate, so it slightly understates the time for a near-full charge.
What charging efficiency should I use?
Home AC charging is typically around 85–92% efficient once onboard-charger and thermal losses are counted; DC fast charging is often a little higher. If you are unsure, 90% is a reasonable default.
Does a bigger battery always take longer?
For the same percentage top-up and charger, yes — more kWh to move means more time. But a bigger battery also usually adds more range per minute, so the time per mile can be similar.
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Educational estimate. Real-world results vary with conditions, tuning and measurement.