kW to Amps Calculator
Kilowatts are just watts × 1,000, so the conversion is amps = (kW × 1,000) ÷ volts. A 5 kW load on a 240-volt circuit draws about 20.8 amps.
Voltage
20.8 amps
5 kW on a 240-volt circuit draws about 20.8 amps.
Will it trip the breaker? That's well within a 30-amp circuit (safe continuous limit 24A). It's getting close to that 30A circuit's comfortable limit — don't pile much else on it.
Runs in your browser — nothing is sent anywhere. Estimates assume nominal voltage and ideal conditions; confirm with a licensed electrician and local code before sizing wire or breakers.
What each breaker can safely carry
The raw rating vs. the safe continuous load (the 80% rule — what actually keeps the breaker from tripping on a load running 3+ hours).
| Breaker | Watts @120V | Watts @240V | Safe continuous @120V |
|---|---|---|---|
| 15 A | 1,800 W | 3,600 W | 1,440 W |
| 20 A | 2,400 W | 4,800 W | 1,920 W |
| 30 A | 3,600 W | 7,200 W | 2,880 W |
| 40 A | 4,800 W | 9,600 W | 3,840 W |
| 50 A | 6,000 W | 12,000 W | 4,800 W |
The formula
Multiply kW by 1,000 to get watts, then divide by the voltage. Amps = (kW × 1000) ÷ Volts. (Divide by power factor too for motors.)
Example: A 9.6 kW EV charger on a 240-volt circuit: 9600 ÷ 240 = 40 amps — which, as a continuous load, needs a 50-amp breaker (the 80% rule).
One caveat that keeps people safe: This is a guide for estimation only. Conversions assume nominal voltage and ideal conditions; real installations vary with power factor, voltage drop, temperature, wire type, and continuous vs. brief use. It doesn't replace the National Electrical Code or a licensed electrician — always confirm with a pro and local code before sizing wire, breakers, or circuits.
Hiring out the wiring?
Before you pay anyone to touch your panel or wiring, make sure they're actually licensed. You can check a contractor's license on StateCreds — our sister site.
Verify a contractor's license by state →Common questions
- How many amps is a 5kW load?
- About 41.7 amps at 120V, or 20.8 amps at 240V. Generators and large appliances are usually on 240V, so use that voltage.
- What breaker do I need for a kW rating?
- Convert to amps, then apply the 80% rule for anything running 3+ hours: a 40-amp continuous load needs a 50-amp breaker. EV chargers are continuous loads, so size up.
- Is this single-phase or three-phase?
- This is single-phase, which covers virtually all homes (120/240V). Three-phase (commercial, 208V/480V) uses a different formula with a √3 factor — size that with an electrician.
Sizing a charger or generator is one thing; what it costs to run is another.
EV charging cost →