Gas Meter Reading to kWh Calculator
Your gas meter measures volume, but your bill charges energy. This calculator applies the prescribed domestic conversion factors so you can compare a bill with your own readings or estimate what a period of use came to.
Use our referral link, and we'll both get £50 credit once your switch is complete.
Existing customer? Find out how you can benefit too. T&Cs apply (only one switching offer per household)
Department for Energy Security and Net Zero publishes a UK average of 39.56 MJ/m³ for 2025, on the gross basis your bill converts on. Yours varies by area and month, and your bill prints it.
Why gas is billed in kWh
A gas meter records volume in cubic metres or cubic feet, while your bill charges for the energy in that gas. The calorific value printed on the bill accounts for the gas's energy content.
The conversion formula
Metric: kWh = (cubic metres × calorific value × 1.02264) ÷ 3.6
- 1.02264 corrects the volume for temperature and pressure.
- The calorific value supplies the energy content.
- Dividing by 3.6 converts megajoules to kWh.
Metric and imperial meters
Metric meters read in cubic metres. Older imperial meters read in hundreds of cubic feet, so the calculator applies the 2.83 conversion before the remaining formula. Check the unit printed on the meter or bill.
Checking your bill
If your result differs from the bill, check the calorific value, meter type, reading dates and whether the supplier used an estimated reading. Small differences can also come from rounding.
To turn these kilowatt hours into money, use the gas bill calculator, which takes your unit rate and standing charge. For what gas costs across the market, see the gas market data page.
Frequently asked questions
How do I convert gas m³ to kWh?
Multiply the cubic metres used by the volume correction factor of 1.02264, then by the calorific value in megajoules per cubic metre, then divide by 3.6. At the calorific value of UK grid gas, one cubic metre is a little over 11 kWh — the calculator starts from the figure DESNZ publishes for the latest year and shows which year that is.
What is the volume correction factor?
For the domestic calculation shown here, the Gas (Calculation of Thermal Energy) Regulations prescribe 1.02264. It adjusts the metered volume for temperature and pressure before the calorific value is applied.
What calorific value should I use?
The calorific value varies by region and over time and is maintained between 38 and 41 megajoules per cubic metre. Your bill prints the figure used for that billing period. Enter that number for the closest comparison with your supplier calculation rather than relying on the UK annual-mean default.
My meter reads in cubic feet. What do I do?
Older imperial meters count in hundreds of cubic feet. Select the imperial option and the calculator multiplies the reading difference by the prescribed 2.83 factor to convert it to cubic metres before applying the rest of the formula.
Other calculators
- £Calculator
Gas Bill Calculator
Calculate your gas bill over any time period using your standing charge, unit rate and daily usage.
Open calculator → - £Calculator
Energy Bill Calculator
Calculate your gas and electricity bill over any time period using your standing charge, unit rate and usage.
Open calculator → - £Calculator
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 →
