Bills & Utilities
UK Gas Meter Reading Calculator
Enter previous and current gas readings, meter type, calorific value, correction factor, and your gas rate to estimate kWh and cost.
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Your result
Based on the values you enter
Ofgem GB Direct Debit rate examples: 1 October to 31 December 2026; checked 14 October. Gas includes 5% VAT; electricity has no VAT for this period. Enter your own bill rates; no extra VAT is added. Comparison quotes and usage are illustrative.
Useful next checks
- Check the inputs before relying on the result.
- Try a second scenario to compare outcomes.
- Read the guide below for context.
# UK Gas Meter Reading Calculator
Convert UK gas meter readings into kWh and estimate the cost using your gas unit rate and standing charge.
What this calculator does
Gas meters usually record volume, while bills charge energy in kWh. This calculator turns metric or older imperial gas meter readings into kWh using the standard UK conversion method, then applies your tariff rates.
How it works
Subtract the previous reading from the current reading to find units used. Metric meters use cubic metres directly. Imperial meters are commonly read in hundreds of cubic feet, so the calculator converts them to cubic metres first.
The kWh formula is:
`cubic metres x calorific value x correction factor / 3.6`
The cost estimate is:
`kWh x pence per kWh / 100 + daily standing charge x days / 100`
Example calculation
For metric readings of 1,200 and 1,300 m3, the volume used is 100 m3. With a calorific value of 39.5 and correction factor 1.02264:
`100 × 39.5 × 1.02264 / 3.6 = 1,122.063333… kWh`
The result shows 1,122.1 kWh. Applying 7.97p/kWh and 29.68p/day for 30 days gives a usage charge of £89.43 plus a standing charge of £8.90, and a total of £98.33, using full precision before display rounding. An imperial reading in hundreds of cubic feet needs the separate ×2.83 conversion first.
How to use the result
Use this to check whether a gas reading looks plausible, estimate a bill between statements, or understand why the number on a gas meter is not the same as the kWh number on a bill.
Assumptions and limitations
The default calorific value is a planning value. Your bill may show a different average calorific value for the billing period. Use the value printed on your supplier bill when you need a closer estimate.
The conversion factors and use of the calorific value from your bill were checked against GOV.UK gas-meter calculation guidance. The 39.5 example is a planning value, not a measured value for your home.
Default rates and sources
Rate examples were checked on 14 October 2026 against Ofgem unit rates and standing charges for 1 October to 31 December 2026. They are Great Britain averages for Direct Debit, not Northern Ireland rates or a quote for every household. Regional, payment-method, meter and tariff differences matter; use your supplier's applicable rates.
Ofgem states that gas figures include 5% VAT, while electricity has no VAT from 1 October 2026 to 31 March 2027. Enter bill rates with any applicable VAT included: the calculator does not add VAT again. This VAT difference also means costs across the affected periods are not directly comparable. Bills crossing a rate-change date should be calculated separately for each part using its own usage, days and rates.
These examples expire after 31 December 2026; they are not a future tariff forecast. Annualised results assume the entered rates stay constant. Usage amounts and comparison offers are editable illustrations, not current official consumption benchmarks or live supplier offers.
Frequently asked questions
Why is gas billed in kWh?
The meter records gas volume, but billing is based on the amount of energy in that gas. The calorific value accounts for energy content.
What is the correction factor?
The correction factor adjusts the measured gas volume for temperature and pressure. UK bills commonly show a factor around 1.02264.
Is my meter metric or imperial?
The meter face should state cubic metres or cubic feet. Newer meters are generally metric, but older imperial meters still exist.
Why is my gas meter not already in kWh?
Gas meters record gas volume. Suppliers convert that volume into kWh using calorific value, correction factor, and a kWh conversion divisor.
Should I use the calorific value from my bill?
Yes. The default is a reasonable planning value, but your bill value is better for checking a specific statement.