EV Charging Time and Cost Calculator
A 60 kWh battery charged from 20% to 80% takes 36 kWh, or 40 kWh from the grid at 90% efficiency. On an 11 kW AC charger that is 40 / 11 = 3.64 h (3 h 38 min). Cost = grid kWh × your price per kWh.
How to use
- Pick AC (home wallbox, Level 1 or 2) or DC fast charging, then enter the usable battery capacity and the charge level you start and stop at.
- Choose a charger preset or type its power. For AC, also enter the onboard charger limit of the car: the slower of the two sets the speed.
- Enter your price per kWh and, if you want the range added, the car efficiency in km/kWh, mi/kWh, kWh/100 km, Wh/km or Wh/mi.
How it works
Energy into the battery = capacity × (target % − current %) / 100. Energy from the grid = battery energy / charging efficiency. You pay for the grid figure.
AC charging time = grid energy / min(charger kW, onboard charger kW). Example: 60 kWh from 20% to 80% is 36 kWh, 36 / 0.9 = 40 kWh from the grid, 40 / 11 kW = 3.64 h (3 h 38 min).
DC fast charging: the onboard charger is bypassed, so only the charger power counts. Above 80% this calculator assumes the power drops to one third. Real taper curves differ by car, battery temperature and charger, so treat the DC time as an estimate.
Default efficiency is 90% for AC and 95% for DC. On AC the car converts AC to DC itself and the onboard charger, battery and cooling lose heat. On DC the conversion happens inside the charger, before the meter that bills you, so fewer losses are counted.
Range added = battery energy × efficiency in km/kWh (other units are converted: 1 mi = 1.609344 km, Wh/km = 1000 / (km/kWh), kWh/100 km = 100 / (km/kWh)).
Charging time by charger power
60 kWh usable battery from 20% to 80% (36 kWh into the battery), default efficiency for each type. AC rows assume an 11 kW onboard charger.
| Charger | Efficiency | Grid kWh | Time |
|---|---|---|---|
| AC 3.7 kW | 90% | 40 | 10 h 49 min |
| AC 7.4 kW | 90% | 40 | 5 h 24 min |
| AC 11 kW | 90% | 40 | 3 h 38 min |
| DC 50 kW | 95% | 37.9 | 0 h 45 min |
| DC 150 kW | 95% | 37.9 | 0 h 15 min |
Typical charger power
- Household outlet: about 1.4 kW at 120 V and 12 A (US Level 1), about 2.3 kW at 230 V and 10 A.
- Single-phase wallbox: 3.7 kW at 16 A or 7.4 kW at 32 A (230 V). US Level 2 at 240 V and 32 A is 7.7 kW.
- Three-phase wallbox: 11 kW at 16 A or 22 kW at 32 A (400 V).
- DC fast chargers: 50 kW for older units, 150 to 350 kW for current high-power chargers. The car may accept less than the charger offers, so enter the lower value.
Where the default efficiency comes from
Measured AC charging efficiency from wall to battery usually falls between about 85% and 95%, for example in the vehicle charging tests published by the U.S. Idaho National Laboratory (Advanced Vehicle Testing Activity). Losses are higher at very low power such as a 120 V outlet, because the car electronics and cooling run for many hours. 90% is a middle value for a wallbox.
With DC charging the AC to DC conversion takes place inside the charger, upstream of the meter that bills the session, so only cable and battery losses remain. 95% is a typical figure. If you know your own numbers, enter them.
Compare with fuel
To compare running costs, take the cost per km or mile shown here and do the same trip in the fuel cost calculator with your petrol or diesel price.
FAQ
How long does it take to charge a 60 kWh battery from 20% to 80%?
On an 11 kW AC wallbox with 90% efficiency it takes about 3 hours 38 minutes and draws 40 kWh from the grid. On a 7.4 kW single-phase charger it is about 5 hours 24 minutes.
Why does my 22 kW charger only deliver 11 kW?
On AC the car converts the power with its own onboard charger. Many cars accept 7.4 kW or 11 kW at most, so a 22 kW wallbox cannot go faster. The calculator uses the lower of the two numbers.
Why does charging slow down after 80%?
As a lithium-ion battery fills up, the car lowers the current to protect the cells. DC fast chargers show this most clearly, which is why road-trip stops usually end around 80%.
Is the cost based on the battery or the grid energy?
On the grid energy, because your meter or the charging station measures what leaves the wall or the charger. The difference is the charging loss.
Which efficiency number should I use for range?
The figure from your trip computer, which is measured at the battery. Official ratings such as EPA kWh/100 mi include charging losses, so with them use the grid energy instead of the battery energy, or raise the efficiency to 100%.
Is an EV cheaper to run than a petrol car?
Compare the cost per km here with the fuel cost calculator. At 0.15 per kWh and 6.5 km/kWh an EV costs about 0.026 per km including charging losses.