kWh to kW Calculator

Kilowatts measure power, the rate at which energy is being used at an instant. Kilowatt-hours measure energy, the total amount used over time. A 2 kW heater running for 3 hours consumes 6 kWh. Your electricity bill charges for kWh consumed, while your supply, cables and any agreed capacity are sized in kW or kVA. Confusing the two is the most common error in energy calculations.

Divide the energy by the time it was consumed over: kW = kWh / hours. The result is the average power across that period, not the peak. For example, 1,000 kWh used over 160 working hours is an average demand of 6.25 kW. The shorter and more specific the time window, the closer the average gets to what the load was actually doing.

Each half-hourly settlement period covers 0.5 hours, so multiply the kWh figure by 2 to get the average kW for that period. A read of 12 kWh in one period means an average demand of 24 kW. Half-hourly data is the most useful consumption data a business has: the highest half-hour in a month is what network capacity and maximum demand calculations are based on.

Because most sites do not run flat out around the clock. A site averaging 6 kW across a month may still peak at 40 kW when machinery, HVAC and catering equipment start together. The ratio between average and peak demand is the load factor, and a low load factor means you are paying for network capacity that sits idle most of the time. Half-hourly data shows you exactly where the peaks fall.

No. A monthly total tells you the average demand but hides the shape of the load entirely. Two sites can consume identical kWh while one peaks at three times the other. Maximum demand needs half-hourly interval data or a maximum demand meter. This matters commercially: if your peaks approach your agreed supply capacity in kVA, you risk excess capacity charges, and if they sit far below it you may be paying for capacity you never use.