Rates & sources
UK energy unit rates vary by region and supplier. Ofgem publishes a price cap refreshed each quarter.
Source: Ofgem — Energy price cap — figures refreshed at the start of each tax year.
Upgrade · £9.99
Full 2025/26 tax summary as a PDF
A personalised 4-page report with your band breakdown, NI, pension relief and sources — delivered to your inbox. No subscription.
When to use this calculator
- Before switching supplier, upgrading equipment, or comparing energy-saving changes.
- When you want to test different usage assumptions or price scenarios quickly.
- When you need a simple estimate before requesting installer or supplier quotes.
- When you are evaluating solar panels, a heat pump, or insulation and want to check the payback period before spending.
- When your tariff is about to change and you want to quickly model the impact on your annual energy bill.
A realistic UK planning example
Use these sample inputs as a quick scenario test, then change one variable at a time to compare outcomes.
Gas Usage Per Day (m³)
15
Unit Rate (p/kWh)
5%
Standing Charge (p/day)
15
After entering these figures, review daily usage, monthly cost and annual together rather than in isolation — each metric tells a different part of the story. Then rerun the tool with one input adjusted to see which variable has the biggest effect on all three outputs before you settle on a plan.
How to read your results
Daily Usage
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Monthly Cost
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Annual
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Method & assumptionsAuthoritative sources
This calculator works out your estimated gas bill by taking your average daily usage in kWh, multiplying it by the unit rate on your tariff, and adding the daily standing charge over your chosen period. Usage figures can be found on a recent gas bill or taken from a smart meter in-home display. Because gas consumption varies significantly with the seasons, the calculator is most accurate when you enter usage figures that reflect the period you are planning for — use a winter month's reading to project winter costs rather than an annual average. Gas VAT in Great Britain is charged at the reduced rate of 5%, and suppliers quote their rates inclusive of this, so no additional adjustment is needed. Actual bills may differ due to meter reading cycles, direct debit smoothing, and any standing charge changes mid-contract.
Common mistakes
- !Using optimistic assumptions without testing a more cautious scenario as well.
- !Comparing outputs from different tools without checking that the inputs match.
- !Treating the result as a final quote instead of a planning estimate.
- !Using the current tariff rate without accounting for future price changes, which can make payback calculations look more favourable than they really are.
- !Forgetting to include the standing charge when comparing annual energy costs, which can be a significant portion of a typical bill.
What to do next
- Run the same scenario with a 10% higher unit rate to see how your figures would look if prices rise.
- Compare this result with a related energy or insulation calculator before requesting installer quotes.
- Use the linked guides to understand export tariffs, grant eligibility, or supplier comparison approaches.
- If you are evaluating an upgrade, get at least two installer quotes and rerun this calculator with the actual cost figures before committing.
- Set a reminder to rerun the calculation when your tariff renews, so the payback estimate stays accurate.
Frequently asked
Use arrow keys to navigate items, Enter or Space to expand/collapse.
End-of-article next steps
Where to go after this calculator
Move to a focused hub instead of restarting your research from scratch.
Best Tools for Small Business
Pick software, validate unit economics, and execute workflows with one connected path.
Open hub →
Startup Resource Center
A startup stack for software decisions, runway math, and practical launch workflows.
Open hub →
Creator Toolkit
Choose creator platforms, calculate revenue targets, and ship assets faster.
Open hub →
Money Management Tools
A practical path for financial product choices, scenario math, and planning utilities.
Open hub →