Energy Bill Calculator
Your energy bill = (Usage in kWh × Unit rate) + Standing charges. The average UK household pays around £1,568/year for dual fuel under the current price cap.
How much should your energy bill be? This calculator estimates your electricity and gas costs based on your usage, unit rates, and standing charges. You can use it with electricity only or include gas for a full dual-fuel estimate.
If you do not know your usage, typical UK household consumption is around 2,700 kWh electricity and 11,500 kWh gas per year.
More Save money calculators · All calculators · All guides
What this calculator does
This calculator estimates your energy bill by multiplying your electricity and gas usage (in kWh) by the unit rates, then adding daily standing charges. It shows monthly and annual totals with a clear breakdown.
Who it is for
Homeowners and renters who want to estimate or check their energy bills, anyone comparing energy tariffs, people moving to a new property, or anyone budgeting household costs.
How to use it
Enter your electricity usage in kWh (monthly or annual). The unit rate and standing charge default to current UK price cap rates but you can adjust them to match your tariff. Toggle 'Include gas' to add gas costs. Click 'See My Result' for your estimate.
How the calculation works
Electricity cost = (kWh usage × unit rate in pence) + (standing charge in pence × days). Gas cost follows the same formula. Monthly standing charges use 30.44 days (365 ÷ 12). All amounts are converted from pence to pounds.
Worked example
Electricity: 250 kWh/month at 24.5p/kWh = £61.25 usage + £18.76 standing charge (61.64p/day × 30.44) = £80.01/month. Gas: 1,000 kWh/month at 6.76p/kWh = £67.60 usage + £9.63 standing charge = £77.23/month. Total: £157.24/month (£1,886.90/year).
Assumptions and limitations
- Default unit rates and standing charges use Ofgem price cap rates — your actual tariff may differ
- Does not account for seasonal variation in usage (you use more gas in winter)
- Monthly calculation uses 30.44 days (365 ÷ 12)
- Does not include VAT — domestic energy is charged at 5% VAT which is usually included in your bill
- Actual bills may vary due to meter readings, estimated vs actual usage, and tariff changes
Frequently asked questions
How do I estimate my energy bill?
Multiply your electricity usage (kWh) by the unit rate, add the standing charge, then do the same for gas if applicable. Our calculator does this automatically with current UK default rates.
What is a standing charge?
A standing charge is a fixed daily fee your energy supplier charges regardless of how much energy you use. It covers the cost of supplying energy to your property and maintaining the network.
Can I calculate gas and electricity together?
Yes — toggle 'Include gas' in this calculator to add gas usage, unit rate, and standing charge. You will see separate breakdowns for each fuel plus a combined total.
Related calculators
- Commute Cost Calculator — Your commute cost = fuel cost (based on distance, MPG, and fuel price) + parking + tolls, multiplied by commute days per week. Work-from-hom
- Electricity Cost Calculator — Electricity cost = (Wattage ÷ 1,000) × Hours used × Electricity rate per kWh. A 2,000W appliance running for 1 hour at 24.5p/kWh costs about
- EV vs Petrol Cost Calculator — EV energy cost = miles ÷ miles/kWh × electricity rate. Petrol fuel cost = miles ÷ MPG × 4.546 × fuel price per litre. Compare annually to se
- Fuel Cost Calculator — Enter your journey distance and fuel economy to find out how much your trip will cost in fuel, with weekly, monthly, and annual estimates.
- Land Registry Fee Calculator — Use this Land Registry fee calculator to estimate the HM Land Registry registration fee for common property applications in England and Wale
- Mortgage Overpay vs Save Calculator — Compare mortgage interest saved from overpayments against interest earned by saving the same amount. If your mortgage rate exceeds your savi
Related guides
- How to Estimate Your Energy Bill — Understand how energy bills are made up, what unit rates and standing charges mean, and how to estimate your monthly costs.
- How to Calculate Fuel Cost Per Journey — A simple guide to working out how much any car journey costs in fuel, with tips for reducing your fuel costs.
- How Savings Interest Works in the UK — Everything you need to know about savings interest rates, compound interest, AER, and the Personal Savings Allowance.
- How to Work Out Electricity Costs for Any Appliance — A simple guide to calculating how much any appliance costs to run, with common examples and money-saving tips.
- EV vs Petrol Running Costs Compared — How much cheaper is an EV to run than a petrol car? A practical comparison of energy costs, maintenance, and cost per mile.
- Should I Overpay My Mortgage or Save? — When mortgage overpayments make sense, when saving is better, and how to compare the two options.
Sources and references
Ofgem price cap (https://www.ofgem.gov.uk/check-if-energy-price-cap-affects-you), Typical domestic consumption values (https://www.ofgem.gov.uk/information-for-household-consumers/energy-price-cap)
Last updated
Last reviewed: 2026-04-12.