Electricity Cost Calculator
Estimate how much an appliance costs to run using its power rating, usage time and electricity unit rate. Calculate cost per use, daily, weekly, monthly and yearly costs, with optional standing charge and multiple-use settings.
Calculate electricity running cost
Enter the appliance power, how long it runs, how often you use it and your electricity rate. This is useful for heaters, tumble dryers, TVs, gaming PCs, kettles, ovens, washing machines and other household appliances.
Quick appliance presets
| Power used | — |
| Energy per use | — |
| Energy per day | — |
| Energy per week | — |
| Electricity rate used | — |
| Standing charge included | — |
How it works
The calculator converts the appliance power into kilowatts, multiplies it by the running time to estimate energy use in kilowatt-hours, then multiplies that by the electricity unit rate. It scales the result by daily use, weekly use, an average month and a full year. If you add a standing charge, that is added separately because it is a fixed daily cost rather than an appliance usage cost.
Formula used
energy used = power in kW × hours used
usage cost = energy used in kWh × price per kWh
daily cost = cost per use × uses per day + standing charge
yearly cost = daily cost × 365
Worked example
Example: 2 kW heater for 3 hours at 24.5p/kWh
cost = 6 × £0.245 = £1.47
So, running a 2 kW heater for 3 hours at 24.5p/kWh costs about £1.47, excluding standing charge.
Common mistakes
Confusing watts and kilowatts
1,000 W equals 1 kW. A 2,000 W heater is a 2 kW heater.
Forgetting time
Power rating alone does not tell you cost. A high-power appliance used briefly can cost less than a low-power appliance running all day.
Including standing charge incorrectly
Standing charge is a fixed daily bill cost. It should not usually be assigned to one appliance unless you deliberately want total bill impact.
Ignoring thermostats and cycling
Heaters, fridges and air conditioners may not draw full rated power continuously because thermostats cycle on and off.
Common questions
How do I calculate electricity cost?⌄
What does kWh mean?⌄
Should I include standing charge?⌄
Why might my real bill be different?⌄
Sources, assumptions and disclaimer
This calculator is for general household cost estimation. It uses the power, time and electricity rate you enter. It does not fetch live tariffs or guarantee your bill.
- Power: appliance labels usually show maximum rated power, but actual power can vary during use.
- Unit rate: enter your own tariff rate from your energy bill for the most useful estimate.
- Standing charge: this is treated as a fixed daily cost and added separately.
- Thermostats: heaters, fridges, freezers and air conditioners may cycle rather than run at full power continuously.
- Disclaimer: this is an estimate only and is not financial, tariff, electrical safety or energy-efficiency advice.