Electricity Cost Calculator
Calculate how much an appliance costs to run.
Enter watts, usage hours, and electricity rate to see daily, monthly, and yearly costs.
Electricity cost calculation tells you how much it costs to run any appliance — a fridge, TV, electric heater, or car charger — based on wattage, hours of use, and your electricity tariff.
The formula: Daily cost = (Wattage × Hours used per day / 1000) × Unit rate (pence per kWh) Annual cost = Daily cost × 365
Converting watts to kilowatts: 1 kWh = 1,000 Wh, so 1,000W for 1 hour = 1 kWh
Worked examples:
Electric kettle: 3,000W kettle, used 6 times a day for 2 minutes each = 12 minutes = 0.2 hours Energy: 3,000 × 0.2 / 1000 = 0.6 kWh/day At 28p/kWh: 0.6 × 28 = 16.8p/day = £61/year
Fridge-freezer (always on): 150W, 24 hours/day Energy: 150 × 24 / 1000 = 3.6 kWh/day At 28p/kWh: £1.01/day = £368/year
Electric heater (2,000W): Used 5 hours/day for 5 winter months (150 days): Energy: 2,000 × 5 / 1000 = 10 kWh/day Cost: 10 × 28p = £2.80/day × 150 days = £420 for the season
UK energy price cap (2024–2025): Unit rate: approximately 24–29p/kWh Standing charge: approximately 50–60p/day (separate fixed charge regardless of usage)
Energy-saving tips:
- A-rated appliances use ~50% less energy than G-rated
- LED bulbs (10W) use 85% less than old incandescent (60W)
- Tumble dryer vs washing line: £150–£200 saving per year
- Heating one degree lower: approximately 10% saving on heating bills