Energy Bill Calculator United Kingdom
This energy bill calculator turns your annual gas and electricity use into a yearly and monthly UK bill, at Ofgem price cap rates or your own tariff.
What it does
The Energy Bill Calculator estimates your annual and monthly gas and electricity cost from your usage and the unit rates and standing charges — defaulting to the current Ofgem price cap, or your own tariff.
Data sources & parameters
The figures below drive this calculator. We keep them aligned with the latest official guidance, and each result recalculates automatically whenever a value changes.
| Parameter | Value | Source | Last updated |
|---|---|---|---|
| Ofgem cap electricity unit rate (p/kWh) | 26.32 | ofgem.gov.uk | Effective 2026-10-01Ofgem price cap for 1 October to 31 December 2026, announced 26 August 2026. Typical direct-debit household 1,723 pounds a year, up 4 per cent. Electricity is VAT zero-rated over this window, so its cash rates cannot be compared with the previous quarter. |
| Ofgem cap gas unit rate (p/kWh) | 7.97 | ofgem.gov.uk | Effective 2026-10-01Ofgem price cap for 1 October to 31 December 2026, announced 26 August 2026. Typical direct-debit household 1,723 pounds a year, up 4 per cent. Electricity is VAT zero-rated over this window, so its cash rates cannot be compared with the previous quarter. |
| Ofgem cap electricity standing charge (p/day) | 54.83 | ofgem.gov.uk | Effective 2026-10-01Ofgem price cap for 1 October to 31 December 2026, announced 26 August 2026. Typical direct-debit household 1,723 pounds a year, up 4 per cent. Electricity is VAT zero-rated over this window, so its cash rates cannot be compared with the previous quarter. |
| Ofgem cap gas standing charge (p/day) | 29.68 | ofgem.gov.uk | Effective 2026-10-01Ofgem price cap for 1 October to 31 December 2026, announced 26 August 2026. Typical direct-debit household 1,723 pounds a year, up 4 per cent. Electricity is VAT zero-rated over this window, so its cash rates cannot be compared with the previous quarter. |
We always strive to use the latest data for every variable so our results and reports are as accurate as possible. Even so, errors are possible — you should not rely on this tool or its report alone, and we accept no liability for any decision made based on it.
The formula
Annual cost = (electricity kWh × rate + gas kWh × rate) ÷ 100 + (standing charges × 365) ÷ 100
How it works
It multiplies your yearly kWh by the unit rate for gas and electricity, adds the daily standing charges over 365 days, and totals them — using the Ofgem cap rates unless you enter your own.
Where it is used
- Estimating your yearly energy bill
- Checking a fixed tariff against the cap
- Budgeting the monthly direct debit
Worked example
Typical usage of 2,700 kWh electricity and 11,500 kWh gas costs about … a year (… a month), including … of standing charges.
An energy bill is your usage times a unit rate, plus a fixed daily standing charge you pay whether you switch anything on or not. This calculator turns your annual gas and electricity usage into a yearly and monthly cost, using Ofgem price cap rates by default or your own tariff.
How your bill is built
Each fuel has two charges. The unit rate is charged in pence for every kilowatt-hour (kWh) you use, so more usage means a bigger bill. The standing charge is a fixed daily amount that covers the network and your connection, and it applies every day of the year. Your total is the usage cost for gas and electricity plus both standing charges over 365 days. The calculator shows each part, so you can see how much of the bill is fixed and how much depends on what you use.
The Ofgem price cap
For households on a standard variable tariff paying by direct debit, Ofgem caps the unit rates and standing charges and updates the cap every three months. The cap is often quoted as one typical household figure, but that assumes a set level of usage; your bill depends on your own consumption. The calculator’s default rates are the cap for October to December 2026, stored as parameters and updated each quarter. If you are on a fixed deal, enter your own unit rates and standing charges in the advanced options.
Knowing your usage
Your annual usage in kWh is on your annual statement or online account and gives the most accurate result. If you do not know it, Ofgem’s typical home figures of about 2,700 kWh of electricity and 11,500 kWh of gas a year are the defaults here. Usage varies a lot with home size, insulation, heating type and the number of people, so adjust them to your own home.
A worked example
A home using 2,700 kWh of electricity and 11,500 kWh of gas at the October to December 2026 cap rates pays about £711 for electricity used, £917 for gas and about £308 in standing charges over a year: about £1,936 in total, or £161 a month. Even a household that used almost no energy would pay over £300 a year just to stay connected, which is why cutting usage helps but cannot remove the bill.
How to use the calculator
Enter your annual electricity and gas usage in kWh. Keep the default rates, or open the advanced options and enter your own tariff’s unit rates and standing charges to check whether a fixed deal beats the cap. The result shows your annual and monthly cost, split into electricity usage, gas usage and standing charges. Use it to set your direct debit, compare tariffs or see the effect of using less.
Assumptions and limitations
This is an estimate. It assumes one flat unit rate per fuel and does not model Economy 7 or time-of-use tariffs with different day and night rates, prepayment meters, regional differences in the cap, the Warm Home Discount or other support, or VAT changes. Standing charges apply for the full 365 days. The default rates are stored as parameters and reviewed each quarter, but because the cap changes every three months, check that they are current or enter your own.
About This Energy Bill Calculator
Use this energy bill calculator to get an instant, accurate estimate. The figures follow official guidance and every rate and threshold is kept up to date for 2026. Adjust the inputs above to match your situation, or browse all our calculators to plan your next step.
Tax year 2026
Frequently asked questions
How is my energy bill calculated?
What rates does the calculator use by default?
What if I do not know my usage?
Why do I pay a standing charge even if I use little energy?
Does the calculator reflect Economy 7 or regional differences?
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