The cap does not cap your bill
This is the most widely believed wrong thing about energy pricing in the UK, and it is believed because the words are misleading rather than because anybody is being careless.
The price cap limits the unit rate and the standing charge. It does not limit the total. When the news reports the cap as a figure in pounds, that number is the annual bill for a household using a stated amount of energy. It is an illustration, not a ceiling.
So a household using twice that much energy pays roughly twice that much money, cap or no cap. Nobody is protected from a large bill by the existence of the cap; they are protected from a large rate.
Part of the bill does not respond to using less at all
The standing charge is paid before a single unit is consumed. On electricity at the current cap that is 57.19p a day, which is £208.75 a year, whether the house is occupied or empty. If you have gas as well there is a second one on top.
That has a consequence people are rarely told. Cutting your usage by 10% does not cut your bill by 10%. It cuts the usage half of the bill by 10% and leaves the other half exactly where it was. The tool works out what that comes to on your figures. Know the real number before you spend money on something promising a percentage off your consumption.
The effect is worst for low users, since a fixed cost is a bigger share of a small bill. That is the household least able to absorb it and the one most likely to be advised to use less.
The cap only applies to some people, and it expires
It applies to standard variable tariffs paid by Direct Debit in England, Scotland and Wales. Northern Ireland is regulated separately by the Utility Regulator and these figures do not apply there.
If you are on a fixed tariff, the cap does not apply to you at all. Put your own rate in instead. Comparing the two is worth doing: a fix below the cap is money saved now and a bet on where the cap goes next.
And the cap changes every quarter. The rates here run to 30 September 2026, with the next published by 26 August. Any calculator quoting a cap rate without a date on it is quoting something that will be wrong within three months.
Why there is no gas rate filled in
The electricity figures on this page were read directly from Ofgem. The gas ones were not, so they are inputs and they stay inputs.
That is a deliberate choice rather than an omission. A plausible-looking default in a bill calculator is worse than an empty box, because an empty box asks you to look at your bill and a filled one does not. Both gas rates sit next to the usage on the statement.
Reading your usage correctly
Usage is the difference between two meter readings, not the reading itself. Entering the reading is the classic way this calculation produces an alarming number, and it is easy to do because the reading is the bigger, more prominent figure on the meter.
For a sense check, a typical household uses around 2,700 kWh of electricity a year. Considerably more than that is entirely normal in an all-electric home, one with a heat pump, or one charging a car, so take a second look if none of those apply.
One last thing that confuses people reading a bill: VAT on domestic energy is already included in the unit rates rather than added at the bottom, so there is nothing further to add to the figures here.
Common questions
Does the price cap mean my bill cannot go above a certain amount?
No. People hear the cap and assume it caps their bill, and it does not: it limits the unit rate and the standing charge, not the total. When a headline gives the cap as a figure in pounds, that is the annual bill for a household using a stated amount of energy, not a ceiling anybody is protected by. Use twice that energy and you pay roughly twice.
Why does using less not save as much as I expect?
Because the standing charge does not move. At 57.19p a day that is £208.75 a year on electricity alone, before a single unit is used, and there is a second one if you have gas. So cutting your usage by 10% cuts your bill by rather less than 10%, and the lower your usage the bigger that gap gets.
What is the standing charge for?
It covers the cost of being connected: the network, the meter, and various levies. It is paid whether the house is occupied or empty and whether you use anything or not. That is why it hits low users hardest as a share of their bill, which is the household most likely to be told to cut their usage.
When does the price cap change?
Every quarter. The current one runs to 30 September 2026 and Ofgem publishes the next by 26 August. If you are on a fixed tariff the cap does not apply to you at all, so put your own rate in instead: the difference can be substantial in either direction.
Why is there no default gas rate?
Because no gas figure has been verified at source for this site. The electricity rates here were read directly off Ofgem; gas was not, and a plausible-looking default in a bill calculator is worse than no default, because it looks like information. Both gas rates are on your bill next to the usage.
My usage looks enormous. What have I done wrong?
Almost certainly entered the meter reading rather than the difference between two readings. Usage is what the meter has advanced by over the period. A typical household uses around 2,700 kWh of electricity a year, so anything over about 5,500 is worth a second look unless the home is all-electric, has a heat pump, or charges a car.