kW to Amps Calculator
Convert kilowatts to amperes for any voltage. Enter the power in kW and voltage to calculate the current in amps. Works for 120V, 240V, and three-phase systems.
How to Convert kW to Amps
The formula to convert kW to amps is: Amps = (kW × 1000) ÷ Volts.This is derived from the power equation P = V × I, rearranged to solve for current. Since kilowatts are thousands of watts, you multiply by 1,000 first before dividing by voltage.
Single-phase: A = (kW × 1000) ÷ V
Three-phase: A = (kW × 1000) ÷ (V × √3)
For example, a 5 kW load at 240 volts draws 20.83 amps (5 × 1000 ÷ 240). The same 5 kW at 120 volts draws 41.67 amps — which is why larger loads like water heaters and HVAC systems use 240V circuits to keep amperage manageable.
For three-phase circuits, the current is lower because power is distributed across three conductors. A 10 kW motor at 480V three-phase draws only 12.03 amps compared to 41.67 amps at 240V single-phase.
kW to Amps Conversion Chart
| kW | @ 120V | @ 240V | @ 480V (3Φ) |
|---|---|---|---|
| 0.5 kW | 4.2 A | 2.1 A | 0.6 A |
| 1 kW | 8.3 A | 4.2 A | 1.2 A |
| 1.5 kW | 12.5 A | 6.3 A | 1.8 A |
| 2 kW | 16.7 A | 8.3 A | 2.4 A |
| 3 kW | 25.0 A | 12.5 A | 3.6 A |
| 5 kW | 41.7 A | 20.8 A | 6.0 A |
| 7.5 kW | 62.5 A | 31.3 A | 9.0 A |
| 10 kW | 83.3 A | 41.7 A | 12.0 A |
| 15 kW | 125.0 A | 62.5 A | 18.0 A |
| 20 kW | 166.7 A | 83.3 A | 24.1 A |
| 25 kW | 208.3 A | 104.2 A | 30.1 A |
| 50 kW | 416.7 A | 208.3 A | 60.1 A |
| 100 kW | 833.3 A | 416.7 A | 120.3 A |
Frequently Asked Questions
How do you convert kW to amps?
Divide kilowatts by voltage, then multiply by 1,000. The formula is: Amps = (kW × 1000) ÷ Volts. For example, 5 kW at 240V equals 20.83 amps (5 × 1000 ÷ 240 = 20.83). For three-phase circuits, also divide by √3 (1.732): Amps = (kW × 1000) ÷ (Volts × 1.732).
How many amps is 1 kW at 120V?
1 kW at 120 volts equals 8.33 amps (1 × 1000 ÷ 120 = 8.33). This is a common calculation for household circuits. A standard 15-amp, 120V circuit can handle about 1.8 kW maximum.
How many amps is 5 kW at 240V?
5 kW at 240 volts equals 20.83 amps (5 × 1000 ÷ 240 = 20.83). You would need at least a 25-amp or 30-amp breaker for this load, accounting for the NEC 80% continuous load rule.
How do I convert kW to amps for a three-phase motor?
For three-phase circuits, use: Amps = (kW × 1000) ÷ (Volts × √3). For example, a 10 kW motor at 480V three-phase draws 12.03 amps (10 × 1000 ÷ (480 × 1.732) = 12.03). Always check the motor nameplate for actual full-load amps, as power factor affects the real current draw.
How many amps does a 7.5 kW motor draw?
At 240V single-phase, a 7.5 kW motor draws about 31.25 amps (7.5 × 1000 ÷ 240). At 480V three-phase, it draws about 9.02 amps (7.5 × 1000 ÷ (480 × 1.732)). Always refer to NEC Table 430.248 or 430.250 for motor full-load current values used in wire and breaker sizing.
What size breaker do I need for a 10 kW load?
At 240V single-phase, 10 kW draws 41.67 amps. Applying the NEC 80% rule for continuous loads, you need a breaker rated at least 52 amps — so a 60-amp breaker. At 480V three-phase, 10 kW draws only 12.03 amps, requiring a 15-amp breaker.
How many amps is 50 kW at 480V three-phase?
50 kW at 480V three-phase equals 60.14 amps (50 × 1000 ÷ (480 × 1.732) = 60.14). You would typically use a 70-amp or 80-amp breaker depending on whether the load is continuous.
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