Energy Bill Estimator

This estimator converts kWh usage into cost by multiplying electricity and gas usage by their unit rates, then adding daily standing charges. Monthly usage is multiplied by 12 before the annual total is calculated; annual usage is used directly.

The default rates are editable and should be treated as price-cap style estimates. Ofgem explains that the cap limits unit rates and standing charges for default tariffs, not your total bill. The July to September 2026 average direct debit cap figures are 26.11p/kWh electricity with a 57.19p daily standing charge, and 7.33p/kWh gas with a 29.04p daily standing charge.

Use the result as a practical planning estimate for electricity kwh, gas kwh, monthly or annual usage, editable unit rates, standing charges, monthly and annual split. The calculator is designed to make the main moving parts visible immediately, so it is most useful when you want to compare scenarios, sense-check a decision, or understand why one input changes the final result.

Before relying on the number, check whether your situation includes anything outside the calculator scope. Common examples are local rules, provider fees, payroll timing, special reliefs, bank holidays, tariff changes, exchange-rate markups, unusual tax codes, or personal circumstances that need official guidance or professional advice.

To make the estimate more accurate, use figures from the most recent bill, payslip, lender quote, receipt, official notice or provider screen you have. Rounded inputs are fine for quick comparisons, but precise inputs are better when you are deciding whether something is affordable or comparing two similar options.

Re-run the calculator whenever a key assumption changes, such as a new rate, different term, changed salary, updated threshold, extra fee, altered usage pattern or different date range. Keeping those assumptions fresh is often more useful than trying to make one calculation perfect.

If you are using the result for a formal decision, keep a note of the inputs you used and the date of the calculation. That makes it easier to compare the estimate with a later quote, bill, payslip or official calculation.