Watts to kVA Calculator

Divide the real power in watts by the power factor, then by 1,000: kVA = W / (PF x 1000). A 180 kW site load at power factor 0.9 is 180000 / (0.9 x 1000), which is 200 kVA. The kVA figure is always equal to or larger than the kW figure, because the power factor of a real installation never exceeds 1. The gap between the two is the reactive power your supply carries without doing useful work.

Because their physical limits are current and voltage, not useful power. A transformer's windings heat up according to the current flowing, whatever the power factor of the load downstream. Rating in kVA (volts x amps) describes what the machine can actually carry. The kW it delivers depends on the load's power factor, which the transformer manufacturer cannot know in advance. That is why this conversion matters: a 200 kVA transformer feeds 180 kW at PF 0.9, but only 160 kW at PF 0.8.

Mixed commercial loads typically land between 0.85 and 0.95. Sites heavy with induction motors, compressors or older fluorescent lighting sit at the lower end; offices dominated by modern IT equipment with power factor correction sit at the top end. The most reliable source is your half-hourly meter data or a recent bill, which often states average power factor. If you only have a nameplate kW figure and no measurement, 0.9 is a sensible planning assumption.

Your connection agreement with the distribution network operator sets an agreed supply capacity (ASC, sometimes called maximum import capacity) in kVA. Exceeding it can trigger excess capacity charges on your bill and, if the overrun is persistent, you may need to apply for a formal capacity increase, which can involve network reinforcement. Converting new plant from kW to kVA at a realistic power factor before connection is the simple way to check headroom in advance.

Yes, and it is often the cheapest capacity you can buy. A 100 kW load at power factor 0.8 draws 125 kVA, but the same load corrected to 0.95 draws about 105 kVA, freeing roughly 20 kVA of headroom on the same connection. Power factor correction equipment, typically capacitor banks, achieves this without touching the supply agreement. Run the conversion at your current and target power factors to quantify the headroom before pricing the correction kit.