How to Calculate the Running Cost of Any Appliance
That old fridge or space heater — how much is it really adding to your bill? Electricity cost is easy to calculate once you know two numbers, and it can reveal some surprising money drains.
The formula
Cost = power (kW) × hours used × price per kWh. An appliance's wattage is on its label; divide watts by 1,000 to get kilowatts. A 2,000 W heater is 2 kW; run for 5 hours at $0.30/kWh = 2 × 5 × 0.30 = $3 a day.
Watch the always-on devices
Low-wattage devices left on 24/7 (fridges, routers, standby electronics) can quietly cost more over a year than high-wattage things used briefly. Multiply daily cost by 365 to see the annual hit — that's where the surprises hide.
Work it out
Our free electricity cost calculator does the maths for any appliance and timeframe, so you can spot what's worth replacing or unplugging.
Bottom line
Running cost is just power × time × rate. Check the wattage, multiply by your hours and tariff, and annualise it — the biggest savings often come from always-on devices, not the obvious power-hungry ones.
