How to read a gas meter
Read the black or white digits from left to right and ignore any red digits or dials, which show fractions. Take the previous reading on your bill away from today's to get the volume used since then.
From cubic metres to MJ
| Volume used | 50 m³ |
|---|---|
| Heating value (example) | 38.5 MJ/m³ |
| Pressure correction factor (example) | 1.00 |
| Energy billed | 1,925 MJ |
The heating value reflects the energy content of the gas, which changes slightly over time, and the pressure correction factor adjusts for the gas pressure and altitude at your meter. Multiply the MJ by your usage rate, add the daily supply charge for each day, and you have the bill. Check it in the gas bill calculator.
MJ, kWh and units
| 1 MJ | 0.2778 kWh |
|---|---|
| 1 kWh | 3.6 MJ |
| 1 WA gas unit | 3.6 MJ (1 kWh) |
Your meter is identified on your bill by its MIRN (meter installation registration number) in most states, which you need when switching retailers. If the bill says the read was estimated, see estimated meter reads; the same rules apply to gas.
Common questions
Multiply the cubic metres by the heating value and the pressure correction factor, both shown on your bill.
One unit is 3.6 MJ, the same energy as 1 kWh.
3.6 MJ. One MJ is about 0.278 kWh.
Sources
The WA unit definition comes from Energy Policy WA. Conversion figures in the worked example are illustrative. Last checked October 2026. Prices include GST unless we say otherwise.