kW to kVA Calculator
Enter real power in kW and power factor to calculate apparent power in kVA instantly. Used for generator, UPS and transformer sizing.
How do you convert kW to kVA?
Divide kW by the power factor: kVA = kW ÷ PF. An 8 kW load at PF 0.8 equals 8 ÷ 0.8 = 10 kVA. This is the inverse of the kVA to kW formula and is critical when sizing generators and UPS units, which are rated in kVA but loads are usually specified in kW.
kW to kVA Conversion Table (kVA = kW ÷ PF)
| Real Power (kW) | PF 0.7 | PF 0.8 | PF 0.9 | PF 1.0 |
|---|---|---|---|---|
| 1 kW | 1.429 kVA | 1.250 kVA | 1.111 kVA | 1.000 kVA |
| 5 kW | 7.143 kVA | 6.250 kVA | 5.556 kVA | 5.000 kVA |
| 8 kW | 11.43 kVA | 10.00 kVA | 8.889 kVA | 8.000 kVA |
| 10 kW | 14.29 kVA | 12.50 kVA | 11.11 kVA | 10.00 kVA |
| 25 kW | 35.71 kVA | 31.25 kVA | 27.78 kVA | 25.00 kVA |
| 100 kW | 142.9 kVA | 125.0 kVA | 111.1 kVA | 100.0 kVA |
Formula
Where: kVA = apparent power in kilovolt-amps, kW = real power in kilowatts, PF = power factor (0–1).
When You Need kVA: Three Practical Scenarios
You need the kVA figure (not just kW) when selecting a transformer, specifying a generator contract, or reading a utility bill that charges for reactive power. Here are three concrete situations where getting kVA wrong has direct cost consequences:
Scenario 1 — Specifying a distribution transformer for a small factory (30 kW load, PF 0.75).
kVA required = 30 ÷ 0.75 = 40 kVA. If you ordered a 30 kVA
transformer (assuming kW = kVA), it would be overloaded and overheat. Transformer
nameplate ratings are in kVA for exactly this reason: the core heats from apparent
power, not real power alone.
Scenario 2 — Utility reactive-power penalty (75 kW office building, PF 0.72).
kVA = 75 ÷ 0.72 ≈ 104 kVA. Many commercial utility tariffs charge
a penalty when PF falls below 0.9 or 0.95. At PF 0.72 the building draws 104 kVA
of apparent power for 75 kW of real work — adding reactive power correction capacitors
to raise PF to 0.95 would drop required kVA to ~79 kVA and eliminate the penalty.
Scenario 3 — Sizing a rental diesel generator for a construction site (22 kW tool load, PF unknown).
Without knowing the PF, the safe rule is to assume PF ≈ 0.8, giving kVA = 22 ÷ 0.8 =
27.5 kVA. Rental generators are commonly available at 20 kVA, 30 kVA,
and 40 kVA, so you would hire the 30 kVA unit — not the 20 kVA one that appears to have
enough kW headroom on paper.
Frequently Asked Questions
Divide kW by the power factor: kVA = kW ÷ PF. For a 10 kW load at 0.85 PF, the result is 10 ÷ 0.85 ≈ 11.76 kVA.
For mixed AC loads, 0.8 is a widely used conservative default. For motor-dominated loads, 0.85 is common. For data-centre UPS, manufacturers often assume 0.9 PF. Always check the equipment nameplate or data sheet when possible.
Only at PF = 1.0, which occurs with purely resistive loads (electric heaters, incandescent lamps). For all inductive or capacitive loads in AC circuits, kVA > kW.
Multiply kVA by the power factor: kW = kVA × PF. Use the kVA to kW calculator for the reverse conversion.