Gas meter reading to kWh calculator
Turn your gas meter readings into kilowatt hours and see what the gas cost, the way your supplier works it out.
The formula is set in law by the Gas (Calculation of Thermal Energy) Regulations. Price: Ofgem's cap for 1 October to 31 December 2026, 7.97p per kWh on average.
Result
Enter two meter readings to see the kWh and cost.
How gas units become kWh
Gas meters measure volume, but you pay for energy. Suppliers convert one to the other with this sum:
cubic metres × 1.02264 × calorific value ÷ 3.6 = kWh
- 1.02264 corrects the volume for the temperature and pressure of the gas. It is set in law for household meters.
- Calorific value is the energy in a cubic metre of gas, in megajoules. It varies a little with where the gas comes from, and is printed on your bill. The UK average in 2025 was 39.56, from DESNZ.
- ÷ 3.6 turns megajoules into kilowatt hours, as a kWh is 3.6 megajoules.
At the average calorific value, 1 cubic metre of gas is 11.24 kWh.
Imperial meters
Older meters measure in hundreds of cubic feet. Multiply the units by 100 to get cubic feet, then by 0.02831685 to get cubic metres, then use the sum above. If your meter shows "ft³" or "cubic feet", choose imperial.
Checked 13 November 2026.