Energy Calculators
Free tools to help you understand your energy bills and make better decisions.
Standing Charge Calculator
Work out how much your daily standing charge is costing you per week, month and year for gas and electricity.
Open calculator →Energy Bill Calculator
Calculate your gas and electricity bill over any time period using your standing charge, unit rate and usage.
Open calculator →Gas Bill Calculator
Calculate your gas bill over any time period using your standing charge, unit rate and daily usage.
Open calculator →Electricity Bill Calculator
Calculate your electricity bill over any time period using your standing charge, unit rate and daily usage.
Open calculator →49 Day Rule Calculator
Find out when you can leave your fixed rate energy tariff for free using the 49-day rule.
Open calculator →Appliance Electricity Cost Calculator
Calculate how much any household appliance costs to run per day, week, month and year.
Open calculator →Solar Panel Calculator
Estimate the cost, savings, and payback period of installing solar panels on your home.
Open calculator →Heat Loss Calculator
Estimate how much heat your home loses in kW, and the indicative heat pump size to look for.
Open calculator →Gas Meter Reading Calculator
Convert gas meter readings to kWh using the same formula your supplier applies, metric or imperial.
Open calculator →Heat Pump Running Cost Calculator
Compare a heat pump against the gas boiler it would replace, using efficiency measured in real British homes.
Open calculator →EV Charging Cost Calculator
Work out what charging your electric car at home costs per charge and per mile, including charging losses.
Open calculator →Is My Energy Bill Normal?
Compare your annual bill against Ofgem's published low, medium and high consumption bands at your own rates.
Open calculator →Standby Power Calculator
Work out what your always-on devices cost each year while doing nothing.
Open calculator →
Frequently asked questions
Are these energy calculators free to use?
Yes. Every calculator on this page is free and does not require an account.
How accurate are the calculator results?
Results are estimates based on the inputs you provide. For best accuracy, use rates and usage figures from your latest bill.
Which calculator should I use first?
If you want an overall bill estimate, start with the Energy Bill Calculator. If you want to analyse one area, use a specialist calculator like standing charge, gas, electricity, appliance cost, or solar.
Can I compare different tariff scenarios?
Yes. Run the same calculator multiple times with different unit rates or standing charges to compare potential costs.