How to read your electricity bill and find your unit rate

From a kettle to an electric car, find out what your electricity use could cost. Use your own UK tariff, compare options and see the assumptions behind every estimate.

Last reviewed: · Methodology

1. Consumption

Check the supply address, meter details and dates covered. Find the opening and closing readings and whether either was estimated. Electricity consumption is shown in kWh. When comparing bills, compare the number of days as well as the total units: a longer billing period can explain a larger bill without a change in daily habits.

2. Electricity price

Find the unit rate and any standing charge. A purely illustrative rate of 25p/kWh becomes £0.25/kWh in the calculator. At that example rate, 20 kWh costs £5 before any separate fixed charges. Check whether tax is already included. If your price changed during the billing period, use the relevant rate for each part.

3. Cost

For the whole bill, add the applicable standing charge multiplied by the number of billed days, then account for payments and adjustments separately. Your account balance and Direct Debit amount do not by themselves reveal an appliance's running cost. Ofgem's price cap in Great Britain is not a cap on the total bill: using more energy can still increase what you pay.

4. Worked example

For Economy 7 or another time-of-use tariff, match consumption to its charging period. Use a consumption-weighted rate only when you need a broad estimate. Northern Ireland has different market arrangements; consult the Utility Regulator and your own supplier rather than applying Great Britain's cap figures. Export payments from solar panels should be recorded separately from electricity bought from the grid.

Data sources

Last reviewed: 2026-09-08

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