Turn the kWh you have used into a cost in pounds, with or without the standing charge.
| Item | Calculation | Cost |
|---|---|---|
| Energy | ||
| Standing charge | ||
| Total |
The result uses the rates you enter. If your bill lists rates before VAT, add the VAT shown on your bill to the total.
Your bill and smart meter talk in kilowatt hours, but what you really want to know is the cost in pounds. This kWh cost calculator converts any number of kWh, or the gap between two meter readings, into money using your unit rate and daily standing charge. The defaults use the Ofgem energy price cap for October to December 2026: 26.32p per kWh and 54.83p a day.
What Is a kWh Cost Calculator?
A kilowatt hour (kWh) is the unit suppliers use to measure electricity. It is the energy a 1,000W appliance uses in one hour. Your bill has two parts: the energy you use, charged per kWh, and a fixed standing charge for each day you are connected, whether you use any power or not.
The formula is: (kWh × unit rate) + (days × standing charge) = total cost. For 225 kWh over 30 days at the price cap, that is £59.22 for energy plus £16.45 in standing charges, so £75.67 in total.
How to Use the kWh Cost Calculator
Step 1: Choose How to Enter Usage
Select kWh used if you already know the figure from your bill, app or smart meter display. Select Meter readings if you want to work it out from two readings taken on different days.
Step 2: Enter Your Usage
Type the kWh used, or enter the start and end readings. The calculator subtracts the start from the end to find the kWh. Ignore any red digits or figures after the decimal point on older meters.
Step 3: Add the Unit Rate and Standing Charge
Enter the unit rate in pence from your tariff. Tick the standing charge box and enter the daily charge and the number of days to include it, or untick it to see the cost of the energy alone.
Step 4: Check the Breakdown
You get the total cost and a table splitting energy and standing charges. To estimate a full year of gas and electricity together, the energy bill calculator works from your annual usage instead. The panel also shows the average cost per day and your effective price per kWh once the standing charge is spread across your usage.
Converting Watts to kWh Cost
To go from watts to kWh, multiply the wattage by the hours used and divide by 1,000. A 1,500W heater on for 2 hours uses 3 kWh. Multiply that by the unit rate to get the cost in pounds, or use the electricity cost calculator to price any appliance by its wattage and hours of use. The table below shows common amounts at 26.32p per kWh, without the standing charge.
| kWh used | Example | Cost at 26.32p |
|---|---|---|
| 1 kWh | 1,000W for 1 hour | £0.26 |
| 3 kWh | 1,500W heater for 2 hours | £0.79 |
| 10 kWh | A day of light use | £2.63 |
| 225 kWh | A typical month | £59.22 |
| 2,700 kWh | Ofgem typical yearly use | £710.64 |
A full year of standing charges at 54.83p a day adds £200.13. Rates vary slightly by region, so check the Ofgem regional unit rates and standing charges if you are on a standard variable tariff.
Frequently Asked Questions
How do I convert kWh to pounds?
Multiply the kWh by your unit rate in pence, then divide by 100. For example, 100 kWh × 26.32p = 2,632p, which is £26.32.
How much is 1 kWh of electricity in the UK?
Under the Ofgem price cap from 1 October to 31 December 2026, the average is 26.32p per kWh for direct debit customers. Fixed tariffs can be higher or lower.
What is a standing charge?
It is a fixed daily fee that covers the cost of keeping your home connected to the grid. You pay it even if you use no electricity.
How do I work out kWh from meter readings?
Subtract the earlier reading from the later one. If your meter read 12,450 last month and 12,675 now, you used 225 kWh.
Does the calculator include VAT?
It uses the rates you enter. Check your bill: if your unit rate and standing charge are shown before VAT, add the VAT listed on your bill to the total.
How many kWh does a typical UK home use?
Ofgem uses 2,700 kWh of electricity a year as typical for a medium user, which is about 225 kWh a month.