Watts to kVA Calculator
Convert watts to kilovolt-amps (kVA) using power factor: kVA = W ÷ (PF × 1,000). Find the generator, UPS or transformer size for your load.
W
APPARENT POWER
5.88 kVA
IN VA
5,882 VA
FORMULA
kVA = W/(PF×1000)
💡 How to Convert Watts to kVA
To convert watts to kVA, divide the watts by the power factor and then by 1,000. The result is the apparent power your supply equipment must be rated for. Because the power factor is at most 1, the kVA needed is always at least the kilowatt figure.
Watts to kVA formula
kVA = W ÷ (PF × 1,000)
Example: 5,000 W at PF 0.85 → 5,000 ÷ (0.85 × 1,000) = 5.88 kVA
Example: 5,000 W at PF 0.85 → 5,000 ÷ (0.85 × 1,000) = 5.88 kVA
Worked examples
- Home backup load of 2,400 W at PF 0.8: 2,400 ÷ 800 = 3 kVA of generator capacity.
- Office IT load of 8,000 W at PF 0.9: 8,000 ÷ 900 = 8.89 kVA UPS rating.
- Electric heating of 10,000 W at PF 1.0: 10 kVA.
Watts to kVA table
| Watts | kVA @ PF 0.8 | kVA @ PF 0.85 | kVA @ PF 0.9 | kVA @ PF 1.0 |
|---|---|---|---|---|
| 500 | 0.62 | 0.59 | 0.56 | 0.5 |
| 1,000 | 1.25 | 1.18 | 1.11 | 1 |
| 1,500 | 1.88 | 1.76 | 1.67 | 1.5 |
| 2,000 | 2.5 | 2.35 | 2.22 | 2 |
| 2,400 | 3 | 2.82 | 2.67 | 2.4 |
| 3,000 | 3.75 | 3.53 | 3.33 | 3 |
| 5,000 | 6.25 | 5.88 | 5.56 | 5 |
| 8,000 | 10 | 9.41 | 8.89 | 8 |
| 10,000 | 12.5 | 11.76 | 11.11 | 10 |
| 20,000 | 25 | 23.53 | 22.22 | 20 |
| 50,000 | 62.5 | 58.82 | 55.56 | 50 |
Sizing tips
- Add the running watts of everything that will run at the same time, then convert to kVA.
- Allow for motor starting. Motors, compressors and pumps can draw several times their running current for a moment at start-up, so generators feeding them need extra capacity beyond the running kVA.
- Leave headroom. Running equipment continuously at 100% of its rating shortens its life; 20–25% spare capacity is common practice.
Related conversions: kVA to watts · kW to kVA · kW to VA
kVA = watts ÷ (power factor × 1,000). 5,000 W at PF 0.85 needs 5.88 kVA.