The calculation is detailed on your bill PDF.
The calculation on the bill will give a precise figure for that month, as it takes into account the small differences over time of the calorific value.
If you're looking for an approximate (but pretty close) figure for the difference between any two readings, then multiply the metered units (assuming it's cu metres) by 11·15 to give kWh.
If it's an old cu ft meter multiply the units by 2·83 first.
Until earlier today I couldn't fathom out why converting cubic feet to cubic metres you multiplied by 2.83, since 1 cubic foot is approximately 0.028 cubic metres. The confusion crept in due to the fact (as I understand) 1 unit on an imperial meter equals 100 cubic feet not 1 cubic foot.
The confusion crept in due to the fact (as I understand) 1 unit on an imperial meter equals 100 cubic feet not 1 cubic foot.
Your understanding is correct. Confused me at one time too.
Yes. The error on trying to measure a tiny 1 cubic foot of gas would be huge.