Calculators · kVA Calculator

Electrical

kVA Calculator

Find kVA from amps or kW, or turn kVA into amps or kW. Single-phase and three-phase, with your power factor.

Type of circuit

Single-phase or three-phase AC.

Voltage

For three-phase, the line-to-line voltage.

Current

The line current. mA is milliamps.

Power factor (PF)

Optional. Add it to also get kW and kVAR. Above 0 and up to 1, or a percentage like 85%.

How to calculate kVA

A kilovolt-amp (kVA) is 1,000 volt-amps. It measures apparent power, the voltage times the current, whatever part of it does useful work. The part that does work is the real power in kilowatts (kW). The ratio between the two is the power factor (PF), so kW = kVA × PF.

You have	Single-phase	Three-phase
Amps and volts, find kVA	kVA = V × A ÷ 1,000	kVA = √3 × V × A ÷ 1,000
kVA and volts, find amps	A = kVA × 1,000 ÷ V	A = kVA × 1,000 ÷ (√3 × V)
kW and power factor, find kVA	kVA = kW ÷ PF
kVA and power factor, find kW	kW = kVA × PF
Reactive power, in kVAR	kVAR = √(kVA² − kW²)

V is the voltage in volts, A the current in amps. In the three-phase column, V is the line-to-line voltage. These are the formulas that an informational calculator site lists for amps to kVA, and the link between kW, kVA and power factor is the one in a Fluke article on power factor. We opened both in October 2026. To go from watts to amps directly, use the watts to amps calculator. To learn more about the power factor, use the power factor calculator.

Example 1: 50 amps at 240 volts, single-phase

A single-phase load draws 50 A at 240 V and has a power factor of 0.8. In the calculator, use the "Amps to kVA" tab.

Step	Operation	Result
Apparent power	240 × 50 ÷ 1,000	12 kVA
Real power	12 × 0.8	9.6 kW
Reactive power	√(12² − 9.6²)	7.2 kVAR

Example 2: 100 amps at 208 volts, three-phase

A three-phase load draws 100 A on a 208 V line-to-line supply. Choose "AC three-phase" and clear the power factor field if you only need the kVA.

Step	Operation	Result
√3 times voltage	1.7321 × 208	360.27
Apparent power	360.27 × 100 ÷ 1,000	36.03 kVA

Amps to kVA chart

kVA for common currents on single-phase and three-phase circuits. Multiply the amps by the voltage, by √3 for three-phase, and divide by 1,000 to check any cell.

Amps	120 V single-phase	240 V single-phase	208 V three-phase	480 V three-phase
10 A	1.20	2.40	3.60	8.31
20 A	2.40	4.80	7.21	16.63
30 A	3.60	7.20	10.81	24.94
50 A	6.00	12.00	18.01	41.57
100 A	12.00	24.00	36.03	83.14
200 A	24.00	48.00	72.05	166.28

kW to kVA chart

For the same kilowatts, a lower power factor means more kVA. Divide the kW by the power factor to check any cell. The power factors in the header are examples only. Use the value for your own equipment.

Real power	PF 1	PF 0.9	PF 0.8	PF 0.7
5 kW	5.00	5.56	6.25	7.14
10 kW	10.00	11.11	12.50	14.29
12 kW	12.00	13.33	15.00	17.14
25 kW	25.00	27.78	31.25	35.71
50 kW	50.00	55.56	62.50	71.43

kVA to amps chart

Line current for a given kVA. Divide the kVA times 1,000 by the voltage, and by √3 as well for three-phase.

Apparent power	240 V single-phase	208 V three-phase	480 V three-phase
5 kVA	20.83	13.88	6.01
10 kVA	41.67	27.76	12.03
25 kVA	104.17	69.39	30.07
50 kVA	208.33	138.79	60.14
75 kVA	312.50	208.18	90.21
100 kVA	416.67	277.57	120.28

kVA is not kW

The two units only match when the power factor is 1. Check which unit a number is in before you compare it with another. If you know the kVA and the power factor, the "kVA to kW" tab gives the real power. If you know both kW and kVA, the power factor calculator finds the power factor.

What this calculator does not do

It gives the apparent power or the current of a balanced load from the numbers you type. It does not choose a transformer, a generator, a wire gauge, a breaker or a fuse, and it does not apply any margin. For a breaker, see the breaker size calculator, and for a whole home, see the electrical load calculator. The electrical code adopted where you live and the equipment makers' instructions set the final rules, and a licensed electrician should confirm them. Nothing you type leaves your browser.

Frequently asked questions

How do I calculate kVA?

Multiply the voltage by the current and divide by 1,000. For a single-phase circuit, kVA = volts × amps ÷ 1,000. For a three-phase circuit, kVA = √3 × line-to-line volts × amps ÷ 1,000. For example, 50 amps at 240 volts single-phase is 240 × 50 ÷ 1,000 = 12 kVA. If you know the kilowatts instead, divide them by the power factor.

Is 1 kVA equal to 1 kW?

Only when the power factor is 1. The kilowatts are the kVA times the power factor, so kW = kVA × PF. At a power factor of 0.8, 1 kVA is 0.8 kW. At a power factor of 1, as in a purely resistive load, 1 kVA is exactly 1 kW.

What is 12,000 watts in kVA?

12,000 watts is 12 kW. Divide by the power factor to get kVA. At a power factor of 1 it is 12 kVA. At 0.9 it is 13.33 kVA. At 0.8 it is 15 kVA. At 0.7 it is 17.14 kVA. The lower the power factor, the more kVA the same wattage needs.

How do I calculate kVA from kW?

Divide the kilowatts by the power factor: kVA = kW ÷ PF. A 10 kW load with a power factor of 0.8 needs 10 ÷ 0.8 = 12.5 kVA. Use the "kW to kVA" tab, type the power with its unit and the power factor.

How do I convert kVA to amps?

Multiply the kVA by 1,000 and divide by the voltage. For three-phase circuits, also divide by √3 and use the line-to-line voltage. For example, 25 kVA at 240 volts single-phase is 25,000 ÷ 240 = 104.17 amps, and 75 kVA at 480 volts three-phase is 75,000 ÷ (1.7321 × 480) = 90.21 amps.

What power factor should I use?

Use the value on the nameplate or data sheet of the equipment if it lists one. A purely resistive load has a power factor of 1. If you do not know the value, use 1 to see the lowest kVA the load can have. A real load with a lower power factor will have a higher kVA than the result shown. This page does not suggest typical values for motors or other equipment.

Can I use this to size a transformer or a generator?

No. The result is only the apparent power of the load from the numbers you type. Choosing a transformer or a generator depends on more than that, including the equipment maker's instructions and the electrical code adopted where you live. Ask a licensed electrician or the equipment supplier.