Energy Bill Calculator

We've created this electricity and gas bill calculator to help you estimate how much you should be expecting to pay for your energy over any set period of time.

This is both an electricity bill calculator and a gas energy bill calculator. You can use it to calculate either gas or electricity bills (or both these utility bills together!)

This may be because you are moving home and want to work out how much more or less you may have to pay, or maybe you are looking to switch tariffs and see how much you could save on your utility bills. Whatever your reason, keep reading to see how to use our free energy bill calculator and find out what you need to know.

Are you being overcharged?

A total on its own does not tell you whether it is fair. What does is your unit rate and standing charge next to the maximum Ofgem allows for your region and payment method — the two things the price cap actually limits.

How to use our electricity and gas energy bill calculator

You need to start by deciding how many days you want to look at, one day, one week, one year or anything in between.

Next, enter the electricity and gas used over whichever unit you selected — for example, kWh per month when the period is months. Use a recent bill where possible; the Ofgem bands below are benchmarks, not household estimates.

The next two pieces of information you will need to get from your utility bill will differ depending on your energy supplier and tariff.

Your unit rate is how much you pay for each unit of electricity, and your standing charge is a fixed amount you pay per day regardless of how much energy is used.

Once you put all these details in, you will automatically see a breakdown of your total unit charge over the period you set, the total cost of your standing charge, and your overall bill for that period of time.

What is a Unit of Electricity?

One unit of electricity is one kilowatt-hour (kWh): 1,000 watts used for one hour. These are exact arithmetic examples if the device draws the stated power constantly:

The total units you consume are recorded on your electricity meter and are used to calculate your electricity bill, based on the unit rate charged by your energy provider.

What is a Unit of Gas?

Gas is billed in kilowatt-hours (kWh), but a gas meter usually records cubic metres (m³) or cubic feet (ft³). This bill calculator expects the converted kWh printed on your bill. If you have two meter readings instead, use the gas meter reading calculator with the correct meter type and your bill's calorific value.

The calculation factors in:

• Volume of gas used (m³ or ft³)
• Calorific value (the energy content of the gas)
• Correction factor (to adjust for pressure and temperature differences)

The total units of gas consumed in kilowatt-hours (kWh) are used to calculate your gas bill based on the unit rate your supplier charges.

What is a Daily Standing Charge?

A daily standing charge is the fixed pence-per-day part of your tariff, charged regardless of energy use. This calculator multiplies each entered standing rate by the number of calendar days and adds it to that fuel's unit-rate cost.

How much electricity a typical UK household uses

If you do not know your own usage, Ofgem publishes Typical Domestic Consumption Values — three bands rather than a figure per bedroom. The medium band is the one used to quote a typical annual bill, including under the price cap.

Low is a flat or a small, well-insulated home, often one or two people; Medium is the figure quoted as “typical” across the industry, including on the price cap; High is a larger home, or more people, or both.

Source: Ofgem, Review of typical domestic consumption values, in force since 1 July 2026 (decision ofgem-tdcv-2026). The monthly and daily columns are the annual figure divided by 12 and by 365; Ofgem publishes the annual figure only. These are single-rate figures. An Economy 7 or other multi-register meter has its own set, and a household on one uses about a third more.

These values changed on 1 July 2026. The medium band was 2,700 kWh before that, so a bill quoted on the older figure is not comparable — the assumption moved, not the household. Real usage varies with the age of the property, how it is heated, how many people live there and the time of year, and is far higher in winter than any annual average implies.

How much gas a typical UK household uses

If you do not know your own usage, Ofgem publishes Typical Domestic Consumption Values — three bands rather than a figure per bedroom. The medium band is the one used to quote a typical annual bill, including under the price cap.

Low is a flat or a small, well-insulated home, often one or two people; Medium is the figure quoted as “typical” across the industry, including on the price cap; High is a larger home, or more people, or both.

Source: Ofgem, Review of typical domestic consumption values, in force since 1 July 2026 (decision ofgem-tdcv-2026). The monthly and daily columns are the annual figure divided by 12 and by 365; Ofgem publishes the annual figure only. Ofgem publishes one set of gas values rather than splitting them by meter type.

These values changed on 1 July 2026. The medium band was 11,500 kWh before that, so a bill quoted on the older figure is not comparable — the assumption moved, not the household. Real usage varies with the age of the property, how it is heated, how many people live there and the time of year, and is far higher in winter than any annual average implies.

We also have a gas bill calculator and electricity bill calculator available.