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Enter your previous and current meter readings below to instantly estimate your UK gas bill using the current Ofgem price cap rates for 2026. Supports both metric (m³) and imperial (cu ft) gas meters.
Unit Rate
6.24p/kWh
Standing Charge
31.43p/day
VAT
5%
Important: Please rely on a professional, accredited Gas Safe engineer and accredited tools for all measuring. This calculator provides estimates only and accepts no liability for calculations.
Working out your gas bill from meter readings involves five straightforward steps. This is the same process your energy supplier uses to calculate your bill each quarter or month.
Locate your gas meter and note down the current reading. Only record the numbers before the decimal point (ignore any red digits or digits after the decimal point). Write down the date so you know the period covered.
Take your previous meter reading (from your last bill or the last time you read the meter) and subtract it from the current reading. This gives you the total units of gas used during the period.
Check whether your meter measures in cubic metres (m³) for metric or cubic feet (cu ft) for imperial. This determines whether you need to apply a conversion factor before calculating kWh.
Convert your gas units to kilowatt-hours (kWh) using the standard conversion formula. If you have an imperial meter, first multiply by 2.83 to get cubic metres. Then apply the volume correction factor and calorific value.
Multiply your kWh by the unit rate (6.24p/kWh), add the standing charge (31.43p/day) multiplied by the number of days, then add 5% VAT to get your total estimated gas bill.
kWh = Units (m³) x 1.02264 x 39.5 / 3.6
Usage Cost = kWh x 6.24p
Standing Charge = 31.43p x Number of Days
Total Bill = (Usage Cost + Standing Charge) x 1.05
For imperial meters, first convert units to m³ by multiplying by 2.83 before applying the formula above.
Knowing whether you have a metric or imperial gas meter is essential for calculating your gas bill correctly. Here is how to tell the difference and what it means for your calculations.
To convert imperial readings to metric, multiply your cubic feet reading by 2.83 (since 1 cubic foot = 2.83 litres of volume equivalent in metric terms). For example, if your imperial meter shows 100 units used, that equals 100 x 2.83 = 283 m³ equivalent for the kWh conversion.
The formula used to convert gas meter units to kWh is standardised across all UK energy suppliers. Each component serves a specific purpose in ensuring accurate billing.
This is the difference between your current and previous meter readings, measured in cubic metres. If you have an imperial meter, you first convert to cubic metres by multiplying by 2.83.
The volume correction factor adjusts the measured volume of gas to account for differences in temperature and pressure. Gas meters measure volume at the conditions present at the meter, but billing requires a standardised measurement. The factor of 1.02264 corrects to standard conditions of 15°C and 1013.25 millibars.
The calorific value represents the amount of energy (in megajoules) contained in each cubic metre of gas. It varies depending on the composition of the gas supplied to your area, typically ranging between 37.5 and 43.0 MJ/m³. The value of 39.5 is the standard average used for estimates. Your actual calorific value appears on your gas bill and is published by your gas transporter.
Dividing by 3.6 converts the energy from megajoules (MJ) to kilowatt-hours (kWh). This is because 1 kWh equals 3.6 MJ. All UK energy suppliers are required by Ofgem to bill in kWh so consumers can compare tariffs on a like-for-like basis.
Regular meter readings are key to ensuring your gas bills are accurate and you are not overpaying or underpaying for your energy usage.
Energy experts and Citizens Advice recommend submitting a meter reading at least once a month. This ensures your bills reflect actual consumption rather than estimated usage. Most suppliers allow you to submit readings via their website, app, or by phone. Try to read your meter on the same date each month for consistent tracking.
If you do not submit regular readings, your supplier will send you an estimated bill based on your past usage patterns and average consumption for your property type. Estimated bills are marked with an "E" next to the reading. Over time, estimated readings can drift significantly from your actual usage, leading to a large catch-up bill or credit balance when an actual reading is eventually taken.
If you have a smart meter, readings are sent automatically to your supplier, eliminating the need for manual readings. Smart meters provide half-hourly consumption data, giving you much more detailed insight into your gas usage patterns. You can request a smart meter installation from your energy supplier free of charge. Visit Ofgem for more information about the smart meter rollout.