If your gas meter reading is in cubic meters (m³), this tool converts it into kilowatt-hours (kWh), which is the unit energy suppliers use to charge for gas. It follows the standard industry calculation used on many utility bills.
How to convert gas m3 to kWh
The standard conversion is:
kWh = (m³ × correction factor × calorific value) ÷ 3.6
- m³: gas volume consumed.
- Correction factor: adjusts volume to standard temperature/pressure.
- Calorific value (CV): energy content of gas in MJ/m³.
- 3.6: converts megajoules to kWh.
Worked example
Suppose your bill shows 100 m³ used, correction factor 1.02264, and CV 39.2:
- 100 × 1.02264 × 39.2 = 4,008.75 MJ
- 4,008.75 ÷ 3.6 = 1,113.54 kWh
Your billable gas usage for that period would be about 1,113.54 kWh (before standing charges).
Quick reference table
| Gas volume (m³) | Approx kWh (CV 39.2, CF 1.02264) |
|---|---|
| 10 | 111.35 kWh |
| 25 | 278.38 kWh |
| 50 | 556.77 kWh |
| 100 | 1,113.54 kWh |
| 250 | 2,783.84 kWh |
Why your bill may differ slightly
1) Calorific value changes by region and time
The CV on your bill can vary from one billing period to another. Using your bill’s exact CV gives the most accurate result.
2) Rounding rules vary
Suppliers may round meter readings, intermediate values, or final kWh figures differently. Small differences are normal.
3) Imperial vs metric meters
This calculator is for m³ (metric). If your meter is in cubic feet (ft³), convert that first or use a dedicated ft³-to-kWh calculator.
How to use this result on your gas bill
- Multiply kWh by your unit rate (pence/kWh) to get variable cost.
- Add daily standing charge for total bill amount.
- Compare month-to-month usage trends in kWh for better budgeting.
FAQ
Is this the same formula used by UK suppliers?
Yes, this is the standard bill conversion structure used for metric gas usage.
What is a typical calorific value?
Most domestic bills show values around 39 MJ/m³, but always use the figure printed on your bill for precision.
Can I estimate cost with this page?
Yes. Enter your pence-per-kWh unit rate and the calculator will estimate your variable gas charge.
Tip: Save your monthly m³, kWh, and cost in a spreadsheet to spot seasonal changes and detect unusual usage quickly.