Gas Bill Calculator UK: Free Estimator Tool

Your UK gas bill is calculated by multiplying your gas usage (in kWh) by the unit rate, then adding the standing charge for the billing period. Usage is measured in cubic metres or cubic feet by your meter, then converted to kWh using the calorific value (about 39.5 MJ/m³) and volume correction factor (1.02264). Finally, 5% VAT is added to domestic gas bills.

The standing charge is a daily fixed fee charged by your energy supplier regardless of how much gas you use. As of January 2026, the average UK standing charge is around 31.43p per day. It covers the cost of maintaining the gas network, meter reading, and billing services.

To convert gas meter readings to kWh: 1) Calculate units used (current reading minus previous reading), 2) For metric meters, multiply by 2.83 to convert m³ to cubic feet if needed, 3) Multiply by the calorific value (typically 39.5), 4) Multiply by the volume correction factor (1.02264), 5) Divide by 3.6 to get kWh.

As of January 2026, under the Energy Price Cap, the average gas unit rate is around 6.24p per kWh. This rate can vary by region and supplier. Check your latest bill or energy supplier website for your exact unit rate.

High gas bills can result from: increased usage during cold weather, inefficient boiler (consider getting a gas rate calculation done), poor insulation, incorrect meter readings, or being on a more expensive tariff. Use this calculator with your actual meter readings to verify your bill is correct.

The average UK household uses approximately 12,000 kWh of gas per year. This varies significantly based on property size, insulation quality, boiler efficiency, and heating habits. A well-insulated 3-bed semi might use 8,000-10,000 kWh, while a larger detached home could use 15,000-20,000 kWh.

The Ofgem Energy Price Cap is a limit set by the UK energy regulator on the maximum amount suppliers can charge for each unit of gas and electricity. It's updated quarterly and protects consumers on standard variable tariffs. As of January 2026, the price cap sets gas at around 6.24p/kWh with a 31.43p daily standing charge.

To reduce your UK gas bill: 1) Improve home insulation (loft, walls, windows), 2) Service your boiler annually to maintain efficiency, 3) Install a smart thermostat, 4) Lower your thermostat by 1°C (saves ~10% on heating), 5) Bleed radiators regularly, 6) Switch to a better tariff or supplier, 7) Consider upgrading to a more efficient boiler.

This gas bill calculator UK tool provides estimates based on the Ofgem Energy Price Cap rates. Actual bills may vary slightly based on your specific supplier, regional variations, and exact meter readings. For precise figures, always check your energy statement or contact your supplier directly. This is a beta tool for estimation purposes.

Gross calorific value (GCV) measures total energy content of gas including water vapour. Net calorific value (NCV) excludes energy in water vapour and is typically ~10% lower. UK gas bills use the gross value (about 39.5 MJ/m³). Modern condensing boilers recover some of this extra heat, making them more efficient.