Gas m³ to kWh Calculator
Convert your gas usage in cubic meters (m³) into kilowatt-hours (kWh) using the standard supplier formula.
If both meter readings are entered, the calculator uses: current − previous.
How to convert gas m³ to kWh
Most gas meters measure volume (cubic meters), but your supplier bills you in energy units (kilowatt-hours). That is why a conversion is needed. The result is what appears on your gas bill as “kWh used.”
The conversion is standard across UK suppliers and is based on three factors: volume used, a correction factor, and calorific value.
Standard formula
- Gas used (m³): The volume from your meter or the difference between two meter readings.
- Correction factor: Adjusts measured volume to account for temperature/pressure differences (commonly 1.02264).
- Calorific value (MJ/m³): Energy content of gas; often around 39.0 to 40.0 and shown on your bill.
- 3.6: Converts megajoules to kilowatt-hours.
Where to find these values on your bill
You can usually locate all required numbers on your supplier statement:
- Meter readings: Previous and current values in m³.
- Units used: Sometimes already listed as the difference between readings.
- Calorific value: Printed in the billing breakdown.
- Correction factor: Often fixed in the formula section of your bill.
Worked example
Suppose your usage is 150 m³, correction factor is 1.02264, and calorific value is 39.2.
Your bill may round this value depending on supplier policy. In many cases, the rounded value is used for charging.
Estimate your gas cost
This calculator also includes optional tariff fields:
- Unit rate (p/kWh): Multiplied by kWh used.
- Standing charge (p/day): Added for each day in your billing period.
When both are entered, you get a simple estimate of your bill before discounts or account adjustments.
Common mistakes to avoid
- Using old default calorific values instead of bill-specific values.
- Entering only one meter reading (you need both to calculate usage).
- Mixing units from different periods.
- Forgetting standing charges when estimating total cost.
FAQ
Is calorific value always 39.2?
No. 39.2 is common, but it can vary by region and billing period. For best accuracy, use the exact value from your statement.
Why divide by 3.6?
Because 1 kWh equals 3.6 MJ. The conversion factor turns megajoules into kilowatt-hours.
Should I use meter readings or direct m³ usage?
Either works. If you have both previous and current readings, this tool calculates the difference automatically and uses it.
Final takeaway
If you want to understand or verify your gas bill, converting m³ to kWh is the key step. Use the calculator above to quickly check your usage, compare billing periods, and estimate charges with your tariff values.