Amps to Kilowatts (kW) Conversion Calculator

Enter the current and voltage to convert amps to watts for DC and AC single and three-phase circuits.

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How to Convert Amps to Kilowatts

To convert amps to kilowatts, you can use the Watt’s Law power formula, which states that I = P ÷ V, where P is the power in watts, I is current in amps, and V is voltage in volts.

The amps to kilowatts formula derived from the power formula is:[1]

P(kW) = I(A) × V(V) / 1,000

Thus, the power P in kilowatts is equal to the current I in amps multiplied by the voltage V in volts, divided by 1,000.

Power triangle illustrating the formula to convert amps to kilowatts with kilowatts being equal to amps times volts divided by 1,000

For example, let’s find the kilowatts of power for a circuit with 12 amps of current at 120 volts.

P(kW) = 12 A × 120 V / 1,000
P(kW) = 1,440 W / 1,000
P(kW) = 1.44 kW

Single-Phase AC Circuit Amps to Kilowatts Conversion

Conversion of amps to kilowatts for single-phase alternating current (AC) circuits using the current, RMS voltage, and power factor (PF) can be done with a slightly different formula.

P(kW) = I(A) × V(V) × PF / 1,000

AC electrical power is composed of a real part, expressed in watts (W), and a reactive part, expressed in volt-amps (VA). The magnitude of both real and reactive together is called the apparent power, and the PF gives the ratio of real power to apparent power.[2]

The PF is a property determined by the AC frequency and the amount of inductive or capacitive elements in the circuit.

Thus, the real power P in kilowatts is equal to the current I in amps multiplied by the voltage V in volts multiplied by the power factor PF, divided by 1,000. Try our power factor calculator to get the power factor if needed.

Three-Phase AC Circuit Amps to Kilowatts Conversion

Using Line to Line Voltage

The formula to convert amps to kilowatts for three-phase AC circuits where the current, line to line RMS voltage, and power factor is known is:[1]

P(kW) = I(A) × VL-L(V) × PF × √3 / 1,000

Thus, the power P in kilowatts is equal to the current I in amps multiplied by the voltage V in volts multiplied by the power factor PF multiplied by the square root of 3, divided by 1,000.

This equation is correct when considering one pair of wires in the three-phase system, but when considering all three pairs of wires in the three-phase system, you would need to multiply it by three.

Using Line to Neutral Voltage

The formula to convert amps to kilowatts for three-phase AC circuits where the line to neutral RMS voltage is known is:

P(kW) = I(A) × VL-N(V) × PF × 3 / 1,000

Thus, the power P in kilowatts is equal to the current I in amps multiplied by the voltage V in volts multiplied by the power factor PF multiplied by 3, divided by 1,000.

This formula is correct for the power delivered by all three wires in the three-phase system, but if you’re considering one wire in the three-phase system, you’ll need to divide by three.

How to Convert Amps and Ohms to Kilowatts

It’s also possible to convert amps to kilowatts using circuit resistance with this formula:

P(kW) = I(A)2 × R(Ω) / 1,000

Thus, the power P in kilowatts is equal to the current I in amps squared multiplied by the resistance R in ohms, divided by 1,000.

You might also be interested in our amps to watts calculator.

Equivalent Amps and Kilowatts at 120V AC

Equivalent ampere and kilowatt values at 120 volts.
Current (Amps) Power (Kilowatts) RMS Voltage
1 amps 0.12 kilowatts 120 volts
2 amps 0.24 kilowatts 120 volts
3 amps 0.36 kilowatts 120 volts
4 amps 0.48 kilowatts 120 volts
5 amps 0.6 kilowatts 120 volts
6 amps 0.72 kilowatts 120 volts
7 amps .084 kilowatts 120 volts
8 amps 0.90 kilowatts 120 volts
9 amps 1.08 kilowatts 120 volts
10 amps 1.2 kilowatts 120 volts
11 amps 1.32 kilowatts 120 volts
12 amps 1.44 kilowatts 120 volts
13 amps 1.56 kilowatts 120 volts
14 amps 1.68 kilowatts 120 volts
15 amps 1.8 kilowatts 120 volts
20 amps 2.4 kilowatts 120 volts
25 amps 3 kilowatts 120 volts
30 amps 3.6 kilowatts 120 volts
35 amps 4.2 kilowatts 120 volts
40 amps 4.8 kilowatts 120 volts
45 amps 5.4 kilowatts 120 volts
50 amps 6 kilowatts 120 volts
60 amps 7.2 kilowatts 120 volts
70 amps 8.4 kilowatts 120 volts
80 amps 9.6 kilowatts 120 volts
90 amps 10.8 kilowatts 120 volts
100 amps 12 kilowatts 120 volts

Equivalent Amps and Kilowatts at 240V AC

Equivalent ampere and kilowatt values at 240 volts.
Current (Amps) Power (Kilowatts) RMS Voltage
1 amps 0.24 kilowatts 240 volts
2 amps 0.48 kilowatts 240 volts
3 amps 0.72 kilowatts 240 volts
4 amps 0.96 kilowatts 240 volts
5 amps 1.2 kilowatts 240 volts
6 amps 1.44 kilowatts 240 volts
7 amps 1.68 kilowatts 240 volts
8 amps 1.92 kilowatts 240 volts
9 amps 2.16 kilowatts 240 volts
10 amps 2.4 kilowatts 240 volts
11 amps 2.64 kilowatts 240 volts
12 amps 2.88 kilowatts 240 volts
13 amps 3.12 kilowatts 240 volts
14 amps 3.36 kilowatts 240 volts
15 amps 3.6 kilowatts 240 volts
20 amps 4.8 kilowatts 240 volts
25 amps 6 kilowatts 240 volts
30 amps 7.2 kilowatts 240 volts
35 amps 8.4 kilowatts 240 volts
40 amps 9.6 kilowatts 240 volts
45 amps 10.8 kilowatts 240 volts
50 amps 12 kilowatts 240 volts
60 amps 14.4 kilowatts 240 volts
70 amps 16.8 kilowatts 240 volts
80 amps 19.2 kilowatts 240 volts
90 amps 21.6 kilowatts 240 volts
100 amps 24 kilowatts 240 volts
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References

  1. Miller, C., Ugly’s Electrical References, 2020 Edition, 2020, Jones & Bartlett Learning, 16-23. https://books.google.com/books?id=1kS8DwAAQBAJ
  2. Fiore, J., AC Electrical Circuit Analysis - A Practical Approach, 2022, 274. http://www.dissidents.com/resources/ACElectricalCircuitAnalysis.pdf