Gas m3 to kWh Calculator
Use your gas volume in cubic meters (m³) to estimate energy in kilowatt-hours (kWh), based on the standard billing method used by many suppliers.
Tip: If you enter a unit rate greater than 1, this calculator treats it as pence and converts to pounds automatically.
How to convert gas m3 to kWh
Gas meters often show usage in cubic meters, but your bill is usually charged in kilowatt-hours. To convert gas m³ to kWh, suppliers use a standard formula that adjusts for pressure and energy content.
- Volume (m³): how much gas you used
- Correction factor: usually around 1.02264
- Calorific value: often around 39–40 MJ/m³
- Divide by 3.6: converts megajoules to kWh
Standard formula
kWh = m³ × 1.02264 × calorific value ÷ 3.6
This calculator lets you use default values or enter the exact figures from your gas statement.
Example gas conversion
Suppose your meter reading difference is 100 m³, correction factor is 1.02264, and calorific value is 39.2.
kWh = 100 × 1.02264 × 39.2 ÷ 3.6 = 1,113.54 kWh (approx).
If your tariff is 7.5p per kWh, your usage cost would be roughly £83.52 before standing charges and taxes.
Why your bill and calculator may differ slightly
Small differences are common. Energy suppliers can use:
- regional calorific values updated over time,
- different rounding rules,
- billing period adjustments and tariff bands.
For best accuracy, use the exact correction factor and calorific value shown on your bill for the same date range.
Step-by-step: using this m3 to kWh calculator
- Enter your gas volume in m³.
- Confirm or edit the correction factor.
- Confirm or edit the calorific value.
- Optionally enter your gas unit rate.
- Click Calculate kWh to view energy and estimated usage cost.
Frequently asked questions
What is a typical calorific value for UK gas?
A common figure is around 39.2 MJ/m³, but it can vary. Always use your bill value for precision.
Can I use this for daily, monthly, or annual usage?
Yes. As long as the m³ value matches your chosen period, the kWh result will match that period too.
Does this include standing charges?
No. The optional cost estimate only covers unit consumption (kWh × rate). Add standing charges separately for total bill estimates.
Final tip
If you track your readings regularly, this conversion helps you monitor gas efficiency, compare tariffs, and spot unusual spikes early. Save your monthly m³ and kWh figures to build a clearer energy trend over time.