Three free calculators, built for UK homes and current UK energy prices. Pick the one you need:
EnergyRunning cost & kWh calculatorWhat any appliance costs per hour, day, month and year, and how many kWh it uses.Open calculator →
HeatingRadiator BTU calculatorThe BTU and watts each room needs, including the bigger size for heat pumps.Open calculator →
Damp & mouldDehumidifier running cost calculatorWhat compressor and desiccant dehumidifiers cost to run, per hour and per year.Open calculator →
Why use these calculators?
- UK prices: the default unit rate follows the Ofgem price cap and is updated every quarter. Type in your own rate from your bill for exact figures.
- Instant: results update as you type, with no sign-up and no data collected.
- Explained: every calculator page shows the formula, a worked example and typical figures, so you can check the maths yourself.
FAQs
How accurate are these calculators?
They give a good estimate for planning and comparing. Real costs depend on your tariff, how often thermostats switch on and off, and the appliance's settings. For a new heating system, an installer should do a room-by-room heat loss calculation.
Where does the electricity price come from?
The default is based on the current Ofgem price cap and is reviewed every three months. Check your bill for your own unit rate.