Subtract the previous meter reading (obtained from your last bill) from the current reading on your meter. These are the first 5 digits for metric meters and first 4 digits for imperial meters. Metric metre registering in cubic metres (m³) Imperial metre registering in cubic feet (ft³)

You will find your previous reading at top of the page on the back of your bill.
Multiply the difference by 2.8317 to obtain the volume used in cubic metres. This step is not required for customers with a metric meter.
Multiply the result by the volume correction factor shown on your invoice (1.0191).

Meters do not have built in temperature and pressure converters therefore, in accordance with established gas regulations (Information can be found at http://www.legislation.gov.uk/uksi/1996/439/made/data.pdf) the volume correction figure is added so an accurate bill is sent out.
Multiply this number by the calorific value shown on your invoice in MJ/m3 (26.6774).

The calorific value is a measure of the available heat energy from burnt gas with the level set at 26.6774 respectively. Guernsey Gas has invested in the assets and equipment required to ensure that these CVs are consistently achieved.
Divide the result by 3.6 to obtain the number of kilowatt hours (kWh) used.

This factor is prescribed in the link on step 3. (See page 6 of link)
Multiply this number by the pence per kWh rate to obtain the approximate cost of gas you have used.

How to calculate your bill

Follow the guide below to understand how to calculate your bill.

If you would like to discuss your bill further, please contact our customer services department on 724811.

Online Services