kW to kVA Calculator
Convert kW to kVA, kVA to kW, or find power factor. This page is built for generator sizing, transformer capacity checks, motor loads, UPS sizing, and AC power calculations.
kW to kVA formula
kW measures real power. kVA measures apparent power. The difference exists in AC circuits because some current supports magnetic fields instead of doing useful work. The link between them is power factor.
If power factor is 1.0, kW and kVA are the same number. If power factor is 0.8, a 20 kW load needs 25 kVA of apparent capacity.
Worked example: convert 20 kW to kVA
This is why a generator or transformer often needs a higher kVA rating than the kW load alone suggests.
Common kW to kVA conversion table
| kW | PF 1.0 | PF 0.9 | PF 0.8 | PF 0.75 |
|---|---|---|---|---|
| 5 kW | 5.00 kVA | 5.56 kVA | 6.25 kVA | 6.67 kVA |
| 10 kW | 10.00 kVA | 11.11 kVA | 12.50 kVA | 13.33 kVA |
| 20 kW | 20.00 kVA | 22.22 kVA | 25.00 kVA | 26.67 kVA |
| 50 kW | 50.00 kVA | 55.56 kVA | 62.50 kVA | 66.67 kVA |
Why this matters for generators and transformers
Generators, transformers, UPS units, and inverters are commonly rated in kVA because their current-carrying parts heat according to voltage and current. The usable real power depends on the load power factor. A 100 kVA generator at 0.8 power factor is commonly treated as about 80 kW of real power.
For motor-heavy loads, compressors, welders, pumps, and industrial machines, do not assume a power factor of 1 unless the nameplate confirms it. A lower power factor increases the kVA needed for the same kW load.
Common questions
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Divide kW by power factor. Formula: kVA = kW ÷ PF. For example, 20 kW at 0.8 power factor equals 25 kVA.
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Multiply kVA by power factor. Formula: kW = kVA × PF. For example, 25 kVA at 0.8 PF equals 20 kW.
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kW is real power that does useful work. kVA is apparent power, which combines real and reactive power in AC circuits.
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Use the equipment nameplate value when available. For rough estimates, motors are often estimated around 0.8 to 0.9, while resistive loads such as heaters are close to 1.0.
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Generators are rated in kVA because their alternator capacity is tied to voltage and current. The usable kW output depends on power factor.
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Only when power factor is 1. At a power factor below 1, kVA is higher than kW. At PF 0.8, 1 kW equals 1.25 kVA.
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100 kW at 0.8 PF equals 125 kVA, calculated as 100 ÷ 0.8.
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100 kVA at 0.8 PF equals 80 kW, calculated as 100 × 0.8.
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Yes. First convert kW to kVA using power factor, then use voltage and phase to calculate amps.
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kVA is mainly an AC apparent power term. In DC, watts and kilowatts are normally used because there is no AC power factor phase angle.