EV Charger Amps to kW Chart (120 V, 208 V, 240 V)

A charger's power in kilowatts is its voltage times its charging current. Use the chart for common ratings, or the calculator for any rating and your car's efficiency.

How it works

Power (kW) = volts × amps ÷ 1,000. Estimated range added per hour = kW × 100 ÷ (kWh per 100 miles).

Level 1 (120 V)

Charging current	Power at 120 V	Est. miles added per hour*
8 A	0.96 kW	3.2
12 A	1.44 kW	4.8
16 A	1.92 kW	6.4

Level 2 (208 V and 240 V)

Charging current	Power at 208 V	Power at 240 V	Est. miles added per hour at 240 V*
16 A	3.33 kW	3.84 kW	12.8
24 A	4.99 kW	5.76 kW	19.2
32 A	6.66 kW	7.68 kW	25.6
40 A	8.32 kW	9.60 kW	32.0
48 A	9.98 kW	11.52 kW	38.4
64 A	13.31 kW	15.36 kW	51.2
80 A	16.64 kW	19.20 kW	64.0

*Estimate at 30 kWh per 100 miles (an example efficiency, not a specific car). Miles per hour = kW × 100 ÷ 30. Use the calculator above for your own efficiency.

Worked example: A 48 A charger on 240 V: 240 × 48 = 11,520 W = 11.52 kW; at 30 kWh/100 mi that is about 11.52 × 100 ÷ 30 = 38.4 miles of range per hour. The same 48 A on 208 V is 9.98 kW.

Assumptions

Amps means the current the charger actually delivers to the car (its charging rating), not the breaker size.
Nominal voltage. DOE AFDC notes Level 2 charging uses 240 V in typical residential settings and 208 V in typical commercial settings, so the same current gives less power at 208 V.
The car's onboard charger may limit AC charging below the charger's rating.
Miles-per-hour figures are estimates that assume the efficiency figure already includes charging losses (as EPA label values do).
Not installation advice. DOE AFDC notes a 30-amp (7.2 kW) residential unit requires a dedicated 40-amp circuit under National Electrical Code Article 625; ask a licensed electrician about your home.

Frequently asked questions

How many kW is a 40 amp EV charger?

At 240 V: 240 × 40 = 9,600 W = 9.6 kW. At 208 V: 8.32 kW.

How many kW is a 32 amp EV charger?

At 240 V: 7.68 kW. At 208 V: 6.66 kW.

How many kW is a 48 amp EV charger?

At 240 V: 11.52 kW. At 208 V: 9.98 kW. Whether your car can accept that rate depends on its onboard charger.

How fast is Level 1 charging?

DOE AFDC lists approximately 5 miles of range per hour of Level 1 charging, assuming 1.9 kW, through a 120 V plug. At 12 A, 120 V gives 1.44 kW.

Related calculators

Sources

Formulas and reference values are from these sources. Page last reviewed 2026-10-19.