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