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WattWorth

What will it cost to run?

Calculators for the energy questions that end up on a bill: running an appliance, charging a car, heating with a heat pump, solar panels and backup batteries. Each one shows how it worked its numbers out.

2.000 kilowatt-hours

A 2,000 W heater running for one hour uses 2 kWh: watts × hours ÷ 1,000. Every calculator here starts from that line.

Calculators

Looking for a particular appliance? Browse the appliance cost library for typical power, usage and yearly cost estimates by category.

Your prices

Every calculator uses these. They are saved on this device and nowhere else.

Pick where you live for your local prices.

Electricity

Default Ofgem, 1 Oct – 31 Dec 2026.

Default Ofgem, 1 Oct – 31 Dec 2026.

Gas

Default Ofgem, 1 Oct – 31 Dec 2026.

Default Ofgem, 1 Oct – 31 Dec 2026.