How do I convert kW to amps?

To convert kW to amps, multiply kilowatts by 1,000 to get watts, then divide by voltage. For DC, Amps = kW × 1000 ÷ V. For single-phase AC, Amps = kW × 1000 ÷ (V × PF). For three-phase AC using line-to-line voltage, Amps = kW × 1000 ÷ (√3 × V × PF).

What is the kW to amps formula for DC?

For DC circuits, use A = kW × 1000 ÷ V. Example: 2 kW at 48 V DC is 2 × 1000 ÷ 48 = 41.67 amps. DC calculations do not use power factor because there is no alternating-current phase angle.

What is the kW to amps formula for single-phase AC?

For single-phase AC, use A = kW × 1000 ÷ (V × PF). If the load is purely resistive, PF is usually close to 1. For motors, compressors, and transformers, the power factor is often lower, so the current is higher than the simple watts divided by volts result.

What is the kW to amps formula for three-phase AC?

For three-phase AC using line-to-line voltage, use A = kW × 1000 ÷ (√3 × V × PF). If you are using line-to-neutral voltage instead, use A = kW × 1000 ÷ (3 × V × PF). Most three-phase supply voltages such as 208 V, 400 V, 415 V, and 480 V are normally line-to-line values.

Why does three-phase kW to amps use √3?

The √3 factor appears because line-to-line voltage in a balanced three-phase system is related to phase voltage by the square root of 3. When real three-phase power is calculated using line-to-line voltage, the formula becomes P = √3 × V × A × PF.

Do I need power factor to calculate amps from kW?

For AC real power calculations, yes. Power factor connects real power in kW to apparent power in kVA. A lower power factor means more current is needed to deliver the same real kW. For DC circuits, power factor is not used.

What power factor should I use if I do not know it?

Use PF 1.0 for a mostly resistive load such as a heater. For motors, 0.8 to 0.9 is commonly used for rough estimating if the nameplate power factor is unknown. For accurate design, use the actual equipment nameplate or meter reading.

How many amps is 1 kW at 120 volts?

At 120 V single-phase and PF 1, 1 kW is 8.33 amps. If the power factor is 0.8, the same 1 kW load is 10.42 amps because current increases as power factor decreases.

How many amps is 1 kW at 240 volts?

At 240 V single-phase and PF 1, 1 kW is 4.17 amps. At PF 0.8, 1 kW is 5.21 amps. For 240 V three-phase line-to-line at PF 1, 1 kW is about 2.41 amps.

How many amps is 10 kW at 400 volts three-phase?

At 400 V three-phase line-to-line and PF 1, 10 kW is about 14.43 amps. At PF 0.8, it is about 18.04 amps. This is a common example because 400 V three-phase supplies are widely used in many countries.

Is kW the same as kVA?

No. kW is real power, while kVA is apparent power. The relationship is kW = kVA × power factor. At PF 1, kW and kVA are equal. At PF 0.8, 10 kW requires 12.5 kVA.

Can I use this calculator for motors?

Yes, this calculator can estimate motor current if you enter the motor kW, voltage, phase, and power factor. If the kW value is output shaft power rather than electrical input power, include efficiency so the calculator can estimate the higher electrical input current.

Is kW to amps enough for breaker or wire sizing?

No. This calculator is useful for electrical estimating, but breaker and wire sizing also depend on local code, continuous load rules, insulation type, ambient temperature, conductor material, installation method, motor starting current, and safety factors.

Why is my measured current different from the calculator result?

The most common reasons are wrong power factor, changing load, wrong voltage type, motor efficiency, imbalance between phases, harmonics, or using nameplate maximum current rather than actual running current. The formula is exact only when the input values match the real operating conditions.

Engineering

kW to Amps Calculator

Convert kilowatts to amps for DC, AC single-phase, and AC three-phase circuits. Enter kW, voltage, phase type, power factor, and optional efficiency to estimate current, watts, kVA, horsepower, and the exact formula used.

Power (kW)

Circuit type

Common voltage

Voltage (volts)

Power factor (PF)

Efficiency optional, %

Current

—

Watts—

Electrical input kW—

Apparent power—

Horsepower equivalent—

Formula used—

kW to amps formulas

The formula depends on the type of circuit. kW is real power, amps is current, volts is electrical pressure, and power factor connects real power to apparent power in AC circuits.

DC: A = kW × 1000 ÷ V AC single-phase: A = kW × 1000 ÷ (V × PF) AC three-phase using line-to-line voltage: A = kW × 1000 ÷ (√3 × V × PF) AC three-phase using line-to-neutral voltage: A = kW × 1000 ÷ (3 × V × PF)

kW to amps conversion table

Power	120 V 1φ PF 1	230 V 1φ PF 1	400 V 3φ PF 1	400 V 3φ PF .8
1 kW	8.33 A	4.35 A	1.44 A	1.80 A
2 kW	16.67 A	8.70 A	2.89 A	3.61 A
3 kW	25.00 A	13.04 A	4.33 A	5.41 A
5 kW	41.67 A	21.74 A	7.22 A	9.02 A
7.5 kW	62.50 A	32.61 A	10.83 A	13.53 A
10 kW	83.33 A	43.48 A	14.43 A	18.04 A
15 kW	125.00 A	65.22 A	21.65 A	27.06 A
20 kW	166.67 A	86.96 A	28.87 A	36.08 A
25 kW	208.33 A	108.70 A	36.08 A	45.11 A
30 kW	250.00 A	130.43 A	43.30 A	54.13 A
50 kW	416.67 A	217.39 A	72.17 A	90.21 A
100 kW	833.33 A	434.78 A	144.34 A	180.42 A

The table uses typical formulas and assumes balanced three-phase loads. Actual current may vary with voltage, power factor, motor efficiency, and load conditions.

Worked examples

Example 1 — 5 kW heater at 230 V single-phase, PF 1 A = 5 × 1000 ÷ (230 × 1) A = 21.74 amps Example 2 — 10 kW motor at 400 V three-phase, PF 0.8 A = 10 × 1000 ÷ (√3 × 400 × 0.8) A = 18.04 amps Example 3 — 2 kW load at 48 V DC A = 2 × 1000 ÷ 48 A = 41.67 amps

Choosing the right voltage and phase

For single-phase loads, use the voltage across the load, such as 120 V, 230 V, or 240 V. For three-phase loads, most supply labels use line-to-line voltage, such as 208 V, 400 V, 415 V, or 480 V. Only choose line-to-neutral if your voltage value is phase-to-neutral, such as 230 V in a 400/230 V system.

For resistive loads like heaters, ovens, and incandescent lamps, power factor is usually close to 1. For motors, compressors, pumps, welders, and transformers, power factor can be lower. A lower PF increases current for the same kW, so it matters when estimating cable load, generator size, and apparent power.

kW, kVA, amps, and volts explained

kW is real power — the useful power doing work. kVA is apparent power — volts multiplied by amps in an AC circuit. Power factor tells you how much of the apparent power becomes real power. The relationship is simple: kW = kVA × PF.

This is why two devices can both be rated at 10 kW but draw different current if their power factors are different. A 10 kW load at PF 1 needs 10 kVA. A 10 kW load at PF 0.8 needs 12.5 kVA, so the current is higher.

Common questions

To convert kW to amps, multiply kilowatts by 1,000 to get watts, then divide by voltage. For DC, Amps = kW × 1000 ÷ V. For single-phase AC, Amps = kW × 1000 ÷ (V × PF). For three-phase AC using line-to-line voltage, Amps = kW × 1000 ÷ (√3 × V × PF).
For DC circuits, use A = kW × 1000 ÷ V. Example: 2 kW at 48 V DC is 2 × 1000 ÷ 48 = 41.67 amps. DC calculations do not use power factor because there is no alternating-current phase angle.
For single-phase AC, use A = kW × 1000 ÷ (V × PF). If the load is purely resistive, PF is usually close to 1. For motors, compressors, and transformers, the power factor is often lower, so the current is higher than the simple watts divided by volts result.
For three-phase AC using line-to-line voltage, use A = kW × 1000 ÷ (√3 × V × PF). If you are using line-to-neutral voltage instead, use A = kW × 1000 ÷ (3 × V × PF). Most three-phase supply voltages such as 208 V, 400 V, 415 V, and 480 V are normally line-to-line values.
The √3 factor appears because line-to-line voltage in a balanced three-phase system is related to phase voltage by the square root of 3. When real three-phase power is calculated using line-to-line voltage, the formula becomes P = √3 × V × A × PF.
For AC real power calculations, yes. Power factor connects real power in kW to apparent power in kVA. A lower power factor means more current is needed to deliver the same real kW. For DC circuits, power factor is not used.
Use PF 1.0 for a mostly resistive load such as a heater. For motors, 0.8 to 0.9 is commonly used for rough estimating if the nameplate power factor is unknown. For accurate design, use the actual equipment nameplate or meter reading.
At 120 V single-phase and PF 1, 1 kW is 8.33 amps. If the power factor is 0.8, the same 1 kW load is 10.42 amps because current increases as power factor decreases.
At 240 V single-phase and PF 1, 1 kW is 4.17 amps. At PF 0.8, 1 kW is 5.21 amps. For 240 V three-phase line-to-line at PF 1, 1 kW is about 2.41 amps.
At 400 V three-phase line-to-line and PF 1, 10 kW is about 14.43 amps. At PF 0.8, it is about 18.04 amps. This is a common example because 400 V three-phase supplies are widely used in many countries.
No. kW is real power, while kVA is apparent power. The relationship is kW = kVA × power factor. At PF 1, kW and kVA are equal. At PF 0.8, 10 kW requires 12.5 kVA.
Yes, this calculator can estimate motor current if you enter the motor kW, voltage, phase, and power factor. If the kW value is output shaft power rather than electrical input power, include efficiency so the calculator can estimate the higher electrical input current.
No. This calculator is useful for electrical estimating, but breaker and wire sizing also depend on local code, continuous load rules, insulation type, ambient temperature, conductor material, installation method, motor starting current, and safety factors.
The most common reasons are wrong power factor, changing load, wrong voltage type, motor efficiency, imbalance between phases, harmonics, or using nameplate maximum current rather than actual running current. The formula is exact only when the input values match the real operating conditions.