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kW to Amps
Motor Calculations

Electric Motor kW to Amps

Calculate Full Load Amps (FLA) for AC electric motors. Essential for selecting cables, circuit breakers, and starters.

Motor Current Calculator

Estimates current based on power, voltage, PF, and efficiency

Estimated Full Load Amps
12.56
Amps (A)

Motor Full Load Amps Chart (Approximate)

Values based on 400V 3-Phase, PF 0.85, Efficiency 0.9

Motor kW Approx Amps (400V) Approx Amps (415V)
0.37 kW 0.70 A 0.67 A
0.55 kW 1.04 A 1.00 A
0.75 kW 1.42 A 1.36 A
1.1 kW 2.08 A 2.00 A
1.5 kW 2.83 A 2.73 A
2.2 kW 4.15 A 4.00 A
3 kW 5.66 A 5.46 A
4 kW 7.55 A 7.27 A
5.5 kW 10.38 A 10.00 A
7.5 kW 14.15 A 13.64 A
11 kW 20.75 A 20.00 A
15 kW 28.30 A 27.28 A
18.5 kW 34.91 A 33.64 A
22 kW 41.51 A 40.01 A
30 kW 56.60 A 54.56 A
37 kW 69.81 A 67.29 A
45 kW 84.90 A 81.84 A
55 kW 103.77 A 100.02 A
75 kW 141.51 A 136.39 A
90 kW 169.81 A 163.67 A
110 kW 207.54 A 200.04 A

How to Find Motor Amperage from kW

The nameplate on an electric motor usually provides the power rating in kilowatts (kW) or horsepower (HP). To find the amperage (current draw) for sizing cables and protection, you need to use the full load current formula.

Unlike a simple resistive heater, measuring motor amps requires considering two additional efficiency factors:

  • Power Factor (PF): Represents the phase shift between voltage and current. Typical motors range from 0.75 to 0.90.
  • Efficiency (η): No motor is 100% efficient. Some energy is lost as heat and friction. Typical efficiency is 80% to 95% (0.80 - 0.95).

Example Calculation

For a 11 kW motor connected to a 415V 3-phase supply, with a Power Factor of 0.85 and 90% Efficiency:

I = (11 × 1000) / (1.732 × 415 × 0.85 × 0.90)
I = 11000 / 549.9
I ≈ 20.0 Amps

Frequently Asked Questions

How many amps is 1 kW?+
It depends on voltage and system type. For DC: I = 1000 W ÷ V (e.g., at 230 V, ≈ 4.35 A). For AC single-phase: I = 1000 ÷ (V × PF). For three-phase (L-L): I = 1000 ÷ (√3 × VLL × PF).
How many kilowatts is 1 ampere?+
For DC: kW = (V × 1 A) ÷ 1000. For example, at 240 V → 0.24 kW. For AC systems, multiply by the power factor and use the correct single-phase or three-phase formula.
How many amps make 1 kWh?+
kWh is energy, not current. To relate amps to kWh you must include voltage, power factor (for AC), and time. For example, 10 A at 230 V, PF 1 for 1 hour ≈ 2.3 kWh.
What is 5 kW in amps?+
It depends on voltage, system, and PF. Single-phase 240 V at PF 0.9 → I ≈ 5000 ÷ (240 × 0.9) ≈ 23.15 A. Three-phase 400 V L-L at PF 0.9 → I ≈ 5000 ÷ (√3 × 400 × 0.9) ≈ 8.01 A.
Can you convert kW to amps?+
Yes! You can convert kW to amps if you know the voltage and power factor. Use our calculator above or apply the formula: I = P ÷ (V × PF) for single-phase, or I = P ÷ (√3 × V × PF) for three-phase systems.
What is the kW to amps formula?+
For DC: I = P ÷ V. For single-phase AC: I = P ÷ (V × PF). For three-phase AC (line-to-line): I = P ÷ (√3 × V × PF). P is power in watts, V is voltage, and PF is power factor.
How to calculate kW to amps at 240V?+
At 240V single-phase with PF 0.9: Amps = (kW × 1000) ÷ (240 × 0.9). For example, 5 kW = 5000 ÷ 216 = 23.15 A. Use PF = 1.0 for resistive loads like heaters.
What power factor should I use?+
Use PF 1.0 for resistive loads (heaters, incandescent lights). Use PF 0.85-0.95 for motors, and 0.9-0.98 for modern LED lighting. When in doubt, use 0.85 for a conservative estimate.
What is the difference between single-phase and 3-phase conversion?+
Single-phase uses I = P ÷ (V × PF). Three-phase includes √3 (≈1.732) factor: I = P ÷ (√3 × V × PF). Three-phase carries more power at lower current, making it more efficient for high-power applications.
How to convert generator kW to amps?+
For generator sizing, use the same formulas based on phase type. A 10 kW single-phase generator at 240V, PF 0.9 provides about 46.3 A. For three-phase at 415V, PF 0.85, it provides about 16.4 A per phase.
What is the difference between kW and kWh?+
kW (kilowatts) measures power — the rate of energy use at any instant. kWh (kilowatt-hours) measures energy — total power consumed over time. 1 kW running for 1 hour = 1 kWh.
How to convert kW to amps at 440V three-phase?+
At 440V three-phase (L-L) with PF 0.85: Amps = (kW × 1000) ÷ (1.732 × 440 × 0.85). For 10 kW: 10000 ÷ 647.5 = 15.44 A per phase. This is common for industrial motors.