kW to Amps Calculator

Introduction

This kW to Amps calculator converts kilowatts (kW) to amperes (A) for DC, AC single phase, and AC three phase circuits. Just enter your power, voltage, and power factor, and the tool gives you the current in amps right away. It works for milliwatts (mW), watts (W), kilowatts (kW), and mechanical or electrical horsepower (hp), so you can use it for small electronics or large industrial loads.

Knowing how many amps a device draws is important when you pick wire sizes, circuit breakers, or fuses. Instead of doing the math by hand, this calculator applies the correct formula for each current type. For DC, it divides power by voltage. For AC single phase, it accounts for the power factor. For AC three phase, it uses the line-to-line formula with the √3 factor or the line-to-neutral formula with a factor of 3. The tool also shows a chart of how current changes as voltage goes up or down, so you can see the relationship clearly.

How to Use Our kW to Amps Calculator

Enter your power, voltage, and current type below. The calculator will instantly convert your kilowatts (kW) into amps (A).

Current Type: Pick the type of electrical current you are working with. Choose DC for batteries and solar panels, AC Single Phase for most home outlets, or AC Three Phase for industrial motors and large equipment.

Power: Type in the amount of power. Use the dropdown next to it to select milliwatts (mW), watts (W), kilowatts (kW), mechanical horsepower (hp mech), or electrical horsepower (hp elec). A motor's rated horsepower is the power it delivers at the shaft.³ The power it draws at full load is higher: the horsepower times 0.7457, divided by the motor's full-load efficiency, gives the input in kW.³

Voltage: Type in the voltage of your circuit. Use the dropdown to select millivolts (mV), volts (V), or kilovolts (kV). This value must be greater than zero.

Power Factor: This field only shows for AC circuits. Enter a number between 0.01 and 1. If you do not know your power factor, use 1 for a purely resistive load.⁴ For motors, 0.8 is the low end of the usual range, since motors usually have a power factor between 0.8 and 1.⁵ A motor's power factor drops when it runs below about 50% of full load, and a low power factor means extra current.³ So a lightly loaded motor can draw more current than a result worked out at 0.8.

Voltage Reference: This field only shows for three-phase AC. Choose Line to Line if you measured voltage between two hot wires.³ Choose Line to Neutral if you measured voltage between one hot wire and neutral.³ A service or motor nameplate voltage is a line-to-line value unless it says otherwise.³

Result Precision: Choose how many decimal places you want in your answer. You can pick any number from 0 to 8.

Press Convert to see your result, or press Reset to go back to the starting values. The chart below the result shows how the current changes as voltage goes up or down at your chosen power level.

How to Convert kW to Amps

Converting kilowatts (kW) to amps (A) means finding how much electric current flows through a circuit when you know the power and voltage. Power tells you how fast a device uses energy.¹ Voltage is the difference in electric potential between two points, which is energy per unit of charge.¹ Current, measured in amps, is how fast electric charge flows through the wire. You need both power and voltage to find the current.

The Basic Formula

For a DC circuit, the formula is simple:

I (A) = 1,000 × P (kW) ÷ V (V)¹

You multiply the power in kilowatts by 1,000 to convert it to watts, then divide by the voltage in volts. The answer is the current in amps.

AC Circuits Are Different

AC circuits need one extra value called the power factor (PF). The power factor is a number between 0 and 1 that shows what part of the apparent power (volts × amps) is real power.² A power factor of 1 means the voltage and current are in step and all of it is real power.² Motors usually have a power factor between 0.8 and 1.⁵

For single-phase AC:

I (A) = 1,000 × P (kW) ÷ (PF × V)²

For three-phase AC using line-to-line voltage:

I (A) = 1,000 × P (kW) ÷ (√3 × PF × V)²

For three-phase AC using line-to-neutral voltage:

I (A) = 1,000 × P (kW) ÷ (3 × PF × V)²

√3, the square root of 3, is about 1.732. It appears in three-phase calculations because three-phase power uses three voltage waves 120 degrees apart, which makes line-to-line voltage √3 times line-to-neutral voltage.²

When You Need This Conversion

Electricians and engineers use kW to amps conversion to pick the right wire size, choose the correct circuit breaker, and make sure electrical panels can handle the load. If you know a machine uses 5 kW on a 240V single-phase circuit with a power factor of 0.9, this conversion tells you the wire must carry about 23.15 amps. That current is the starting point for choosing the wire and the breaker. A continuous load is one whose maximum current runs for 3 hours or more.⁷ Where a branch circuit supplies a continuous load, the U.S. National Electrical Code requires wire with an ampacity of at least the noncontinuous load plus 125% of the continuous load, unless the assembly and its breakers are listed for use at 100% of their rating.⁸ The breaker's rating must be at least that same amount, with the same exception.⁹ If the 5 kW machine runs for 3 hours or more, that is at least 1.25 × 23.15 = 28.94 amps. On a long run, also check the voltage drop, since a longer wire has more resistance. The code notes that branch-circuit wire sized so the voltage drop is no more than 3% at the farthest outlet, and no more than 5% in total with the feeder, gives reasonable efficiency.⁸