Convert kilowatts to amperes for single-phase AC, three-phase AC, and DC circuits. Enter kW, voltage, and power factor for accurate current results used in electrical planning.
✓ Verified: NEC 2023 — National Electrical Code Power and Current Relationships — April 2026
kW
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Real power in kilowatts
V
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Supply voltage (e.g. 120, 240, 480)
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Select AC single-phase, three-phase, or DC
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AC only: 0.80-0.95 typical. Enter 1.0 for DC or resistive loads.
Convert kilowatts to amperes for single-phase AC, three-phase AC, and DC circuits. Enter kW, voltage, and power factor for accurate current results used in electrical planning.
Current (Amps)
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⚠️ Disclaimer: These calculations are for estimation and planning purposes. All electrical installations must comply with the NEC and local codes, and must be designed and verified by a licensed electrician. Do not use calculated values as a substitute for nameplate ratings.
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Sources & Methodology
✓ Formulas verified against authoritative sources listed below.
IEEE power systems reference for kW, kVA, and ampere relationships in AC and DC circuits
Methodology: Single-phase AC: A = (kW x 1000) / (V x PF). Three-phase AC: A = (kW x 1000) / (sqrt(3) x V x PF). DC: A = (kW x 1000) / V. NEC minimum conductor rating = 125% of calculated amps (NEC 430.22). Apparent power kVA = kW / PF.
⏱ Last reviewed: April 2026
How to Convert Kilowatts to Amps
Converting kilowatts (real power) to amperes (current) requires knowing the supply voltage and, for AC circuits, the power factor. The formulas differ for single-phase, three-phase, and DC systems. Getting this calculation right is essential for correctly sizing electrical conductors, breakers, and switches — undersized wiring causes dangerous overheating and fire risk.
Single-Phase kW to Amps
Single-phase: Amps = (kW x 1000) / (Volts x PF). Example: 5 kW at 240V with PF 0.85: A = 5000 / (240 x 0.85) = 5000 / 204 = 24.51 amps. For a purely resistive load (electric heater, incandescent bulb) the PF = 1.0, so Amps = kW x 1000 / Volts.
Three-Phase kW to Amps
Three-phase: Amps = (kW x 1000) / (1.732 x Volts x PF). The factor 1.732 (square root of 3) accounts for the three-phase relationship. Example: 10 kW at 480V three-phase, PF 0.90: A = 10000 / (1.732 x 480 x 0.90) = 10000 / 748.2 = 13.37 amps. Three-phase uses less current for the same power, which is why industrial loads use three-phase systems.
DC kW to Amps
DC circuits: Amps = (kW x 1000) / Volts. No power factor needed because DC has no reactive component. Example: 2 kW at 48V DC (common in EV charging and telecom systems): A = 2000 / 48 = 41.67 amps.
NEC Conductor and Breaker Sizing
Per NEC 210.20, branch circuit conductors must be rated at 125% of the continuous load current. Per NEC 240.4, overcurrent protection must match or exceed the conductor ampacity. Always round up to the next standard breaker size: 15, 20, 25, 30, 35, 40, 50, 60, 70, 80, 90, 100 amps, etc. Consult a licensed electrician for actual installations.
1-Phase: A = (kW x 1000) / (V x PF) | 3-Phase: A = (kW x 1000) / (1.732 x V x PF) | DC: A = (kW x 1000) / V
kW = kilowatts (real power). V = supply voltage. PF = power factor (0.80-1.0 for AC). sqrt(3) = 1.7321. NEC 125% minimum conductor rating = calculated amps x 1.25. kVA = kW / PF (apparent power). 1 kW = 1000 W.
Kilowatts to Amps — Common Values
kW
120V 1-Phase (PF 1.0)
240V 1-Phase (PF 0.85)
480V 3-Phase (PF 0.85)
1 kW
8.33 A
4.90 A
1.42 A
2 kW
16.67 A
9.80 A
2.84 A
5 kW
41.67 A
24.51 A
7.09 A
10 kW
83.33 A
49.02 A
14.18 A
15 kW
125.00 A
73.53 A
21.27 A
20 kW
166.67 A
98.04 A
28.35 A
50 kW
416.67 A
245.10 A
70.88 A
100 kW
833.33 A
490.20 A
141.75 A
⚡ Electrical Safety Note: Always use the actual nameplate current rating from equipment when sizing conductors and overcurrent protection — do not rely solely on calculated values. Nameplate ratings account for starting currents, internal losses, and safety margins tested by the manufacturer. Calculated kW-to-amp conversions are useful for planning and estimation only.
Frequently Asked Questions
Single-phase: A = (kW x 1000) / (V x PF). Three-phase: A = (kW x 1000) / (1.732 x V x PF). DC: A = (kW x 1000) / V. You need voltage and power factor for AC circuits.
At 120V single-phase with PF 1.0: A = 1000/120 = 8.33 amps. With PF 0.85: A = 1000/(120 x 0.85) = 9.80 amps.
At 240V single-phase with PF 0.85: A = 5000/(240 x 0.85) = 24.51 amps. With PF 1.0 (resistive): A = 5000/240 = 20.83 amps.
At 480V three-phase with PF 0.85: A = 10000/(1.732 x 480 x 0.85) = 10000/708.7 = 14.11 amps.
For AC induction motors: 0.80 to 0.90 at full load. For resistive loads (heaters, incandescent lights): 1.0. For electronic power supplies: 0.95 to 0.99 (with PFC). For lighting: 0.90 to 0.95. Use 0.85 as a reasonable default if unknown.
Step 1: Calculate amps using the formula. Step 2: Multiply by 1.25 (NEC 125% rule for continuous loads). Step 3: Round up to the next standard breaker size. Example: 24.51 A x 1.25 = 30.64 A. Use a 35A breaker.
kW is real power (does actual work). kVA is apparent power (total power drawn from supply). kVA = kW / Power Factor. For PF = 1.0, kVA = kW. For PF = 0.85, kVA = kW/0.85 (about 18% higher). Generators and transformers are rated in kVA.
PF 1.0: A = 3000/240 = 12.5 amps. PF 0.85: A = 3000/(240 x 0.85) = 14.71 amps. For a resistive heating element (PF = 1.0), 12.5 A. For a motor (PF = 0.85), 14.71 A.
Three-phase power uses three conductors carrying current 120 degrees out of phase, so the effective power is sqrt(3) times greater for the same voltage and current. This means three-phase delivers more power at lower current per phase, which is why large industrial loads use three-phase to reduce conductor size and cost.
kW (kilowatt) is 1000 watts of power. Power is the rate at which energy is used or transferred. A 1 kW device uses 1000 joules of energy per second. Over 1 hour it uses 1 kWh (kilowatt-hour) of energy, which is what electric utilities bill customers for.