How to read your electricity bill
Find the unit rate, standing charge and consumption figures that belong in your electricity calculators, with a transparent worked example.
Reviewed 8 November 2026. Worked figures are hypothetical unless explicitly identified as a sourced reference.
Copy the charge, the unit and the period together
Start with the electricity section, not a combined gas-and-electricity payment. Keep the tariff name, charge dates and whether consumption is measured or estimated beside the numbers you copy. Supplier layouts differ, so use the labels on your actual statement rather than expecting every bill to use the same position or abbreviation.
| Bill item | Meaning for your calculation | Use it here |
|---|---|---|
| Unit rate, p/kWh | The cost for each unit of electricity in that price period. £0.25/kWh and 25p/kWh are the same rate. | All appliance-cost tools. |
| Standing charge, p/day | A daily charge separate from the electricity used. | The whole-bill day/night comparison, not an extra-appliance estimate. |
| Consumption, kWh | Energy used over the stated dates; distinguish this from a cumulative meter register. | A matching-period bill check or annual tariff comparison. |
| Day and night registers | Separate consumption for the applicable price windows. | The actual kWh split in the day/night tool. |
A hypothetical 30-day electricity charge
Suppose a bill covers 200kWh at 25p/kWh and 30 days at 50p/day. Electricity costs 200 × £0.25 = £50. Standing charges cost 30 × £0.50 = £15. The combined charge is £65 before any separately applicable adjustments. These invented rates are not a supplier quote.
Use consistently VAT-inclusive figures when entering our tools. Check how your statement presents tax, credits and discounts instead of adding a percentage again to a figure that already includes it. The cost of a particular period is not necessarily the amount of your regular payment: reconcile charges, payments and any balance separately.
Match the dates before comparing
If a rate changes during a statement, calculate each consumption block at its own rate and add the parts. Do not apply the latest rate retrospectively to all earlier usage. Likewise, do not call a 30-day reading an annual figure. A projection assumes the chosen period represents future use, which may be unsuitable for seasonal heating.
For a simple register check, subtract the earlier cumulative electricity kWh from the later reading for the same register and dates. Use the supplier's stated method where a register resets or a meter changes. An in-home display and a bill can cover different windows or use different pricing settings; a mismatch alone does not identify its cause.
For day/night tariffs, split energy rather than hours
Use day kWh and night kWh from matching dates. Off-peak share is night kWh ÷ total kWh × 100. For example, 80 off-peak kWh out of 200 total is 40%, regardless of the number of off-peak clock hours. Confirm your supplier's actual window and meter arrangement.
Compare both rates and standing charges. Our tool holds the entered rates and annual consumption constant; it does not model changing half-hourly prices, exit fees or every contract adjustment.
Choose the next useful check
- Build a household appliance plan and compare only matching dates and non-overlapping loads.
- Measure an individual appliance if the bill only gives a household total.
- Compare two complete measured jobs without confusing watts and kWh.
If a statement remains unclear, ask the supplier to explain the specific dates, readings and charges. Avoid putting account numbers or a complete bill into site search; these calculators need only the numeric assumptions you choose to enter.
Sources
- Ofgem: how bills are calculated.
- British Gas: understanding your bill — a supplier example, not a universal bill template.
- House of Commons Library: electricity bill components.