What does the Gas Cost Calculator do?

Calculate annual gas bill from kWh usage, unit rate and standing charge. All calculations are performed in your browser using official UK rates and thresholds.

Does this reflect the current energy price cap?

This calculator uses representative energy prices. The Ofgem energy price cap changes quarterly — check Ofgem's website for the latest cap level applicable to your region and payment method.

Can I save money by switching tariff?

Potentially yes. The energy market offers various fixed and variable tariffs. Use a comparison site authorised by Ofgem (such as Ofgem's own comparison tool) to check if switching could save you money.

Gas Cost Calculator

Calculate annual gas bill from kWh usage, unit rate and standing charge.

Last updated: April 2026 · Source: Ofgem — Energy price cap

Annual Gas Usage (kWh)

UK avg: 11,500 kWh

Unit Rate (p/kWh)

Standing Charge (p/day)

Annual Gas Bill

£892.92

Monthly

£74.41

Unit Cost

£777.40

Standing Charge

£115.52/yr

Disclaimer

This calculator is provided for informational purposes only and should not be considered as financial or tax advice. All calculations are performed locally in your browser — no personal data is collected or sent to our servers. Rates and thresholds are sourced from HMRC and GOV.UK and are updated for the current tax year. Always verify results with HMRC or consult a qualified professional before making financial decisions.

How It Works

Gas heating is the most common form of central heating in the UK, used by around 23 million households. The cost depends on your boiler efficiency, thermostat settings, insulation levels and the size of your home. The average gas unit rate is approximately 6.76p per kWh, with a daily standing charge of around 31.65p.

A modern condensing boiler operates at 90-94% efficiency, meaning 90-94p of every pound spent on gas is converted to useful heat. Older boilers may be only 60-75% efficient, wasting 25-40% of the gas consumed. Reducing your thermostat by just 1 degree C can save up to 10% on your heating bill, typically £80-£120 per year.

This calculator estimates your gas costs based on your boiler type and efficiency, thermostat setting, insulation level and property size. It shows monthly and annual costs and models the saving from upgrading your boiler or improving thermostat management.

Example: 3-bed semi, old boiler (80% efficiency), thermostat at 21 C

Estimated annual gas consumption: 12,000 kWh
Gas cost: 12,000 x 6.76p = £811.20
Standing charge: 365 x 31.65p = £115.52
Total annual gas bill: £926.72
Upgrade to 93% efficient boiler: saves ~£130/year
Reduce thermostat by 1 C: saves ~£93/year

Source: Ofgem — Energy price cap

Frequently Asked Questions

What does the Gas Cost Calculator do?: Calculate annual gas bill from kWh usage, unit rate and standing charge. All calculations are performed in your browser using official UK rates and thresholds.
Does this reflect the current energy price cap?: This calculator uses representative energy prices. The Ofgem energy price cap changes quarterly — check Ofgem's website for the latest cap level applicable to your region and payment method.
Can I save money by switching tariff?: Potentially yes. The energy market offers various fixed and variable tariffs. Use a comparison site authorised by Ofgem (such as Ofgem's own comparison tool) to check if switching could save you money.