Kilowatts to Amps Calculator
Convert kilowatts to amps for DC, single-phase, and three-phase circuits.
How do you convert kilowatts to amps?
Multiply kilowatts by 1000, then divide by volts. A 5 kW single-phase load at 240 V draws (5 × 1000) ÷ 240 = 20.8 A. For three-phase, divide by (√3 × V × PF): a 5 kW, 400 V, PF 0.9 motor draws 5000 ÷ (1.732 × 400 × 0.9) = 8.0 A.
kW to Amps Formula
For DC circuits, simply multiply kW by 1,000 to get watts, then divide by voltage.
Power factor does not apply to DC.
Example: 2 kW at 120 V to (2 × 1,000) ÷ 120 =
16.6667 A.
For single-phase AC circuits, divide real power by voltage and power factor.
A lower PF means more current is drawn for the same useful power output.
Example: 3 kW at 230 V, PF 0.85 to (3 × 1,000) ÷ (230 × 0.85) =
15.3374 A.
Use this formula when the voltage given is line-to-line (phase-to-phase), which is the
standard way to specify three-phase voltage (e.g. 208 V, 400 V, 480 V).
√3 ≈ 1.7321.
Example: 10 kW at 400 V (L-L), PF 0.9 to (10 × 1,000) ÷ (1.7321 × 400 × 0.9) =
16.0375 A.
Use this formula when using the line-to-neutral (phase-to-neutral) voltage.
Note: VLN ≈ VLL ÷ √3, so both three-phase formulas give the same result
for the same physical system.
Example: 10 kW at 231 V (L-N), PF 0.9 to (10 × 1,000) ÷ (3 × 231 × 0.9) =
16.0375 A
(same as 400 V L-L example above, since 400 ÷ √3 ≈ 231 V).
kW to Amps Reference Table
All values assume unity power factor (PF = 1.0). For other PF values, use the calculator above.
| kW | 120 V | 208 V | 240 V | 277 V | 480 V |
|---|---|---|---|---|---|
| 1 kW | 8.3333 A | 4.8077 A | 4.1667 A | 3.6101 A | 2.0833 A |
| 2 kW | 16.6667 A | 9.6154 A | 8.3333 A | 7.2202 A | 4.1667 A |
| 3 kW | 25.0000 A | 14.4231 A | 12.5000 A | 10.8303 A | 6.2500 A |
| 5 kW | 41.6667 A | 24.0385 A | 20.8333 A | 18.0505 A | 10.4167 A |
| 7.5 kW | 62.5000 A | 36.0577 A | 31.2500 A | 27.0758 A | 15.6250 A |
| 10 kW | 83.3333 A | 48.0769 A | 41.6667 A | 36.1011 A | 20.8333 A |
| 15 kW | 125.0000 A | 72.1154 A | 62.5000 A | 54.1516 A | 31.2500 A |
| 20 kW | 166.6667 A | 96.1538 A | 83.3333 A | 72.2022 A | 41.6667 A |
| 25 kW | 208.3333 A | 120.1923 A | 104.1667 A | 90.2527 A | 52.0833 A |
| 30 kW | 250.0000 A | 144.2308 A | 125.0000 A | 108.3032 A | 62.5000 A |
| 50 kW | 416.6667 A | 240.3846 A | 208.3333 A | 180.5054 A | 104.1667 A |
Single-phase vs Three-phase vs Power Factor
One live conductor and a neutral. Standard for homes, small offices, and loads up to about 10 kW. For the same power, single-phase draws more current per conductor than three-phase.
A = (kW × 1,000) ÷ (V × PF)Three conductors, each offset 120°. Used in industrial and commercial buildings for motors, HVAC, and large equipment. For the same kW, three-phase requires less current per conductor than single-phase.
A = (kW × 1,000) ÷ (√3 × V × PF)PF measures how efficiently a circuit converts apparent power (kVA) to real power (kW). Resistive loads (heaters, incandescent bulbs) have PF = 1.0. Inductive loads (motors) typically have PF ≈ 0.8. General commercial: PF ≈ 0.9. A lower PF means higher current.
PF = kW ÷ kVAFrequently Asked Questions
Use the formula for your circuit type:
- DC:
A = (kW × 1,000) ÷ V - AC single-phase:
A = (kW × 1,000) ÷ (V × PF) - AC three-phase (L-L voltage):
A = (kW × 1,000) ÷ (√3 × V × PF), where √3 ≈ 1.7321 - AC three-phase (L-N voltage):
A = (kW × 1,000) ÷ (3 × V × PF)
For DC circuits, power factor does not apply. For AC, use PF = 1.0 for resistive loads and PF = 0.8 for typical motors.
- DC at 120 V: (1 × 1,000) ÷ 120 = 8.3333 A
- AC single-phase at 120 V, PF 0.8: (1 × 1,000) ÷ (120 × 0.8) = 10.4167 A
The AC value is higher because a power factor below 1.0 means additional reactive current is drawn that does not contribute to real power.
kW (kilowatts) is real (active) power —
the actual energy doing useful work, such as heat, light, or mechanical motion.
kVA (kilovolt-amps) is apparent power,
which is the total power drawn by the circuit including reactive power.
They are related by: kW = kVA × PF.
For purely resistive loads (electric heaters, incandescent bulbs), PF = 1.0, so kW = kVA. For motors and other inductive loads, kVA > kW. When sizing cables and breakers for AC circuits, use the current calculated from kVA (or from kW ÷ PF) to account for the full apparent power.
- Three-phase L-L at 240 V, PF 0.8: (5 × 1,000) ÷ (1.7321 × 240 × 0.8) = 15.0361 A
- Three-phase L-L at 240 V, PF 1.0: (5 × 1,000) ÷ (1.7321 × 240) = 12.0281 A
Wire sizing depends on current (amps), not directly on watts. At 240 V single-phase with PF = 1.0, 5 kW draws (5 × 1,000) ÷ 240 = 20.83 A.
Per NEC 210.20, continuous loads must be sized at 125%: 20.83 × 1.25 = 26.04 A minimum breaker rating. This requires 10 AWG copper wire (rated 30 A) for most installations. If PF = 0.8, current rises to 26.04 A, and 125% = 32.55 A — requiring 8 AWG copper. Always consult a licensed electrician for actual installation decisions.