Calculator kW to kVA — Instant Conversion with Formula, Table & Examples

Convert electrical input kilowatts to apparent power with kVA = kW ÷ PF. The calculator, tables and six examples use explicitly stated power factors. If your starting value is motor shaft-output kW, divide by motor efficiency first. The result describes running electrical demand; equipment selection requires additional checks.

kW to kVA Conversion Table — Standard Commercial Values

The table compares electrical input kW at three assumed power factors. None is a universal safe default. For example, 20 kW requires 25 kVA at PF 0.80 but 33.33 kVA at PF 0.60. If your starting value is motor shaft-output kW, account for efficiency before using the kW-to-kVA conversion.

How to Convert kW to kVA — Formulas Step by Step

The conversion from kilowatts to kVA depends on one variable: the power factor (PF). The formula is identical for single-phase and three-phase systems because kW and kVA are already total system quantities — the number of phases is already factored in when you measure or calculate them.

Where:

If you know the voltage and current instead, you can reach kVA directly:

Use electrical input kW and the corresponding PF at the same operating point. If a motor nameplate gives shaft-output kW, first divide by motor efficiency. The default PF is an illustrative input rather than a value established for your equipment.

Why does the same formula work for single-phase and three-phase?

Both kW and kVA in this conversion refer to total electrical quantities. For a motor rated 10 kW shaft output at efficiency 0.90 and PF 0.80, input kVA = 10 ÷ (0.90 × 0.80) = 13.89 kVA. If 10 kW is already measured electrical input, the result is instead 10 ÷ 0.80 = 12.50 kVA. No extra √3 factor is used in either conversion.

kW vs kVA — Types and Differences

kW measures active power and kVA measures apparent power. For sinusoidal AC conditions, the power triangle gives kVA² = kW² + kVAR². Do not calculate reactive power by subtracting kW from kVA. With nonlinear loads, use suitable true-power-factor measurements and account for distortion.

In practical terms: when you buy a diesel generator rated 500 kVA and the nameplate says PF = 0.80, you can draw up to 400 kW of real power from it (500 × 0.80 = 400). If your load is 400 kW but has a PF of only 0.70, you actually need 400 ÷ 0.70 = 571.4 kVA — that 500 kVA generator is too small.

kVA to kW — Inverse Conversion

To reverse the conversion, multiply instead of dividing:

Need the full inverse calculator? Use our tool above — just switch the direction to “kVA → kW” and enter your value.

Solved Examples — 6 Real-World Cases

kW to kVA in Electric Motors — Nameplate Reading

Electric motors are the most common load where the kW-to-kVA conversion matters in daily practice. The motor nameplate gives you the output power in kW (or HP), but the transformer and cabling must handle the input power in kVA. The difference comes from two factors: motor efficiency and power factor.

The full chain looks like this:

For example, a 50 kW motor with 93% efficiency and PF 0.84 draws: 50 ÷ (0.93 × 0.84) = 50 ÷ 0.7812 = 64.0 kVA from the supply. That is 28% more apparent power than the shaft output. If you only sized the transformer at 50 kVA, you would overload it.

Always check the motor nameplate for the rated current (FLA — Full Load Amps) and voltage. From these you can also calculate kVA directly: for three-phase, kVA = (V × I × 1.732) ÷ 1000. Both methods should give you the same answer — if they don’t, re-check the efficiency value.

For starting demand, use motor and starter data rather than multiplying every running value by the same factor. Starting current, acceleration and voltage recovery depend on the motor, driven load and source.

Quick Equivalences — kW to kVA

Below are direct answers for the most searched kW-to-kVA conversions. All values assume PF = 0.80 unless otherwise noted. If your power factor is different, use the calculator above for an exact result.

Frequently Asked Questions

How many kVA is 1 kW?

1.25 kVA at a power factor of 0.80. The formula is kVA = kW ÷ PF. At PF = 1.0 (purely resistive loads like electric heaters), 1 kW equals exactly 1 kVA.

What is the formula to convert kW to kVA?

kVA = kW ÷ PF. This single formula works for both single-phase and three-phase systems. Power factor (PF) ranges from 0 to 1 and represents how efficiently the load uses apparent power.

Is the kW to kVA formula different for three-phase?

No. kVA = kW ÷ PF is the same for single-phase and three-phase. The √3 factor only appears when converting from volts and amps to kVA, not from kW to kVA. Both kW and kVA are already total system values regardless of phase count.

What power factor should I use if I don’t know it?

Obtain PF from equipment data or a suitable measurement at the operating load. A utility bill may describe a whole installation rather than one device. If PF is unknown, compare labelled assumptions instead of presenting the default as a measured or safe value.

Why is kVA greater than or equal to kW?

For a consuming AC load with 0 < PF ≤ 1, kVA = kW ÷ PF, so kVA is at least as large as kW numerically. The two are equal at unity PF. The numerical difference kVA − kW is not reactive power in kVAR.

How do I convert 150 kW to kVA?

187.50 kVA at PF = 0.80. Calculation: 150 ÷ 0.80 = 187.50. If the actual PF is 0.85, the result is 150 ÷ 0.85 = 176.47 kVA. Always use the measured or nameplate PF when available.

What is the difference between kW and kVA in a generator?

kW is the real power the generator can deliver to do work (run motors, light bulbs). kVA is the apparent power — the total electrical output including reactive power. A 500 kVA generator at PF 0.80 can supply a maximum of 400 kW of real power.

How do I size a transformer using kW to kVA?

Estimate coincident electrical input kW and the corresponding overall PF to obtain running kVA. Then check starting loads, loading conditions and the transformer manufacturer’s requirements. For mixed loads, the overall PF must represent the combined load; it is not the arithmetic average of individual power factors.

Can kW and kVA ever be equal?

Yes. At unity power factor, kVA and electrical kW are numerically equal. An ideal resistive load is one example. The presence of a motor, capacitor or inductor does not by itself establish the net PF of an entire installation.

How does power factor affect my electricity bill?

The effect depends on the utility tariff, which may charge for kW demand, kVA demand or reactive energy. A kW-to-kVA conversion alone cannot calculate the bill or establish whether power-factor correction will save money.

What is 600 kW in kVA?

750.00 kVA at PF = 0.80. This is one of the most common generator ratings in the industry: 750 kVA / 600 kW. At PF 0.85, the answer is 705.88 kVA. The calculator at the top gives you instant results for any PF.

How do I convert kW to kVA for a three-phase motor?

For electrical input kW, use kVA = kW ÷ PF. For motor shaft-output kW, use kVA = shaft kW ÷ (η × PF). A 50 kW shaft-output motor at η = 0.93 and PF = 0.84 needs approximately 64.00 kVA; 50 kW of measured electrical input at the same PF is 59.52 kVA.

See our kW vs kVA comparison for worked examples and the distinction between power factor and motor efficiency.

Related Conversions

Explore more electrical conversion calculators on our site:

• Amps to kW Calculator — convert current to kilowatts with voltage and PF.
• Amps to Watts Calculator — formula, table and free converter.
• Amperes to VA Calculator — convert amps to volt-amperes for single and three-phase.
• Amps to HP Calculator — convert amperage to horsepower for motors.
• Motor Efficiency Calculator — calculate input vs output power and losses.
• Balanced and Unbalanced Load Calculation — three-phase load distribution.

Technical references

• U.S. Department of Energy: Determining Electric Motor Load and Efficiency — input power, shaft output and load-dependent motor performance.
• Cummins: How to size a genset — factors beyond a running-power conversion.