kW to kVA Calculator
Convert real power (kW) to apparent power (kVA) using power factor — or flip the direction to convert kVA back to kW. Essential for sizing generators, transformers, and UPS systems from a known load.
How to Convert kW to kVA (and Back)
Divide kilowatts by the power factor to get kilovolt-amps.Power factor (PF) is the ratio of real power to apparent power, so rearranging PF = kW ÷ kVA gives both conversion formulas:
kW to kVA: kVA = kW ÷ PF
kVA to kW: kW = kVA × PF
Worked example (kW to kVA): A 100 kW motor load with a power factor of 0.8 requires 100 ÷ 0.8 = 125 kVA of apparent power. A transformer or generator serving this load must be rated at least 125 kVA even though the load only does 100 kW of useful work.
Worked example (kVA to kW): A 50 kVA transformer feeding a load with a 0.9 power factor delivers up to 50 × 0.9 = 45 kW of real power.
The gap between the two numbers is reactive power (kVAR), which circulates in the system without doing useful work — see the power triangle explanation on our kVA calculator page. Improving power factor with correction capacitors shrinks that gap; our power factor calculator shows how much capacitance is needed.
kW to kVA Conversion Chart
Apparent power (kVA) required for common kW loads at typical power factors:
| kW | PF 0.80 | PF 0.85 | PF 0.90 | PF 0.95 | PF 1.00 |
|---|---|---|---|---|---|
| 10 kW | 12.5 kVA | 11.8 kVA | 11.1 kVA | 10.5 kVA | 10.0 kVA |
| 25 kW | 31.3 kVA | 29.4 kVA | 27.8 kVA | 26.3 kVA | 25.0 kVA |
| 50 kW | 62.5 kVA | 58.8 kVA | 55.6 kVA | 52.6 kVA | 50.0 kVA |
| 75 kW | 93.8 kVA | 88.2 kVA | 83.3 kVA | 78.9 kVA | 75.0 kVA |
| 100 kW | 125.0 kVA | 117.6 kVA | 111.1 kVA | 105.3 kVA | 100.0 kVA |
| 150 kW | 187.5 kVA | 176.5 kVA | 166.7 kVA | 157.9 kVA | 150.0 kVA |
| 200 kW | 250.0 kVA | 235.3 kVA | 222.2 kVA | 210.5 kVA | 200.0 kVA |
| 250 kW | 312.5 kVA | 294.1 kVA | 277.8 kVA | 263.2 kVA | 250.0 kVA |
| 300 kW | 375.0 kVA | 352.9 kVA | 333.3 kVA | 315.8 kVA | 300.0 kVA |
| 400 kW | 500.0 kVA | 470.6 kVA | 444.4 kVA | 421.1 kVA | 400.0 kVA |
| 500 kW | 625.0 kVA | 588.2 kVA | 555.6 kVA | 526.3 kVA | 500.0 kVA |
At PF 1.00 (purely resistive loads) kVA equals kW. The lower the power factor, the more kVA capacity a source needs to serve the same kW load — a 500 kW load at PF 0.8 demands 625 kVA.
Frequently Asked Questions
How do you convert kW to kVA?
Divide kilowatts by the power factor: kVA = kW ÷ PF. For example, a 100 kW load with a power factor of 0.8 requires 100 ÷ 0.8 = 125 kVA of apparent power. This is why a generator or transformer serving that load must be rated at least 125 kVA, not 100 kVA.
How do you convert kVA to kW?
Multiply kilovolt-amps by the power factor: kW = kVA × PF. For example, a 100 kVA generator at a power factor of 0.8 can deliver 100 × 0.8 = 80 kW of real power. At unity power factor (1.0), the full 100 kVA would be available as 100 kW.
What is the difference between kW and kVA?
kW is real power — the power actually converted into useful work and the number your utility bills you for. kVA is apparent power — the total volts times amps flowing in the circuit, which determines the current your equipment must carry. They are linked by power factor: kW = kVA × PF, so kVA is always equal to or greater than kW.
What power factor should I use for the conversion?
Use the measured or nameplate power factor if you have it. Common assumptions: 0.8 for standby generator sets and mixed motor loads (the industry-standard generator rating point), 0.85 to 0.95 for modern commercial buildings, and 1.0 for purely resistive loads such as electric heaters. When in doubt for sizing, a lower power factor gives a more conservative (larger) kVA figure.
Is 500 kVA the same as 500 kW?
No, unless the power factor is exactly 1.0. At a typical 0.8 power factor, a 500 kVA source delivers only 400 kW of real power (500 × 0.8). This distinction matters when comparing generator ratings — a 500 kVA / 400 kW genset cannot serve a full 500 kW load.
Can kW ever be greater than kVA?
No. Power factor is the ratio kW ÷ kVA and can never exceed 1.0, so real power can never exceed apparent power. At best they are equal, which happens only with purely resistive loads. Any inductive or capacitive component in the load adds reactive power (kVAR) and pushes kVA above kW.
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