VA to kW Calculator
Convert volt-amps (VA) to kilowatts (kW) using power factor: kW = VA × PF ÷ 1,000. Find the real power a UPS, inverter or generator can deliver.
REAL POWER
21.25 kW
IN WATTS
21,250 W
FORMULA
kW = (VA × PF)/1000
💡 How to Convert VA to kW
To convert VA to kW, multiply the volt-amps by the power factor and divide by 1,000. VA is apparent power; kW is real power, the part that does useful work. The power factor (0 to 1) is the link between them, so you cannot convert without it.
VA to kW formula
Example: 25,000 VA at PF 0.85 → 25,000 × 0.85 ÷ 1,000 = 21.25 kW
Worked examples
- Modern online UPS (PF 0.9): 3,000 VA × 0.9 ÷ 1,000 = 2.7 kW.
- Older line-interactive UPS (PF 0.6): 1,000 VA × 0.6 ÷ 1,000 = 0.6 kW (600 W).
- Industrial load (PF 0.85): 50,000 VA × 0.85 ÷ 1,000 = 42.5 kW.
VA to kW table at common power factors
| VA | PF 0.6 | PF 0.8 | PF 0.9 | PF 1.0 |
|---|---|---|---|---|
| 600 | 0.36 | 0.48 | 0.54 | 0.6 |
| 1,000 | 0.6 | 0.8 | 0.9 | 1 |
| 1,500 | 0.9 | 1.2 | 1.35 | 1.5 |
| 2,000 | 1.2 | 1.6 | 1.8 | 2 |
| 3,000 | 1.8 | 2.4 | 2.7 | 3 |
| 5,000 | 3 | 4 | 4.5 | 5 |
| 10,000 | 6 | 8 | 9 | 10 |
| 25,000 | 15 | 20 | 22.5 | 25 |
| 50,000 | 30 | 40 | 45 | 50 |
| 100,000 | 60 | 80 | 90 | 100 |
Apparent, real and reactive power
AC power has three parts, often drawn as the power triangle. Apparent power (VA or kVA) is voltage × current: what the wiring, breaker and transformer actually carry. Real power (W or kW) is the part that does useful work, such as heat, light or motion. Reactive power (VAR) is the part that flows back and forth to build magnetic and electric fields in motors, transformers and capacitors. The power factor (PF) is the ratio of real to apparent power, between 0 and 1.
Typical power factors: resistive loads such as heaters and incandescent lamps run at 1.0; computer and server power supplies with power factor correction (PFC) run at about 0.95–0.99; induction motors run at roughly 0.8–0.9 at full load and lower when lightly loaded. Diesel generators are conventionally rated at a power factor of 0.8.
Check the watt rating, not just VA
Most UPS and inverter spec sheets list both a VA and a watt rating, and the watt figure is the true limit for real power. If only VA is given, calculate kW with a conservative power factor (0.6–0.8) or ask the manufacturer before sizing your load.