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We subtract your previous reading from your current reading to find the units consumed.
Calculate your gas bill from your meter readings · no sign-up
Gas bill calculator UK
Calculate your gas bill from two meter readings. Choose a metric or imperial meter, enter your tariff and the days between readings, then see your gas usage in kWh, usage cost, standing charge and VAT.
Only need to convert units? Use the gas units to kWh calculator. For a full bill estimate, use the form below.
- ✓ Instant calculation
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- ✓ Runs in your browser
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How to calculate your gas bill from meter readings
Subtract the readings, convert the gas used to kWh, then apply your tariff for the same billing period.
Follow a worked gas bill calculation or compare typical gas costs and usage.
Convert to kWh
Units are converted using your meter type, volume correction and calorific value.
Add charges and VAT
We apply your unit rate, daily standing charge and domestic energy VAT at 5%.
Example: 35 metric gas units over 30 days
A previous reading of 12,345 and a current reading of 12,380 gives 35 m³. Using a calorific value of 39.25 and volume correction of 1.02264, that is 390.24 kWh.
At an illustrative 7p/kWh and 30p/day, both before VAT, the usage costs £27.32 and the standing charge is £9.00. Adding 5% VAT gives an estimated bill of £38.13. Use your own tariff and conversion factors; these are example rates.
See the full calculation method, check metric and imperial conversion examples, or measure your boiler’s gas running cost.
Reading your meter
Metric or imperial?
A metric meter is marked m³. An older imperial meter is marked ft³. Only enter the digits before the decimal point or any red digits.
See how to read each type of gas meterNews and practical guidance
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