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Page last updated on 19th June 2025

Our FAQs: How to calculate your energy bill

Understanding how to read your energy bill can seem daunting but, given concerns about the price of energy, it’s become even more important. Taking the time to understand your energy bill is one a good way to prioritise your finances effectively and gain greater control over your household outgoings.

This guide will outline exactly what is an energy bill and address frequently asked questions such as “how can I work out my energy bill?” and “how much will my energy bill be?” We will also offer tips on how to spot errors or discrepancies in your bill, helping you manage your energy usage and spending more efficiently.

What's on this page?

What is an energy bill?
What are the key sections of an energy bill?
How do tariff types have an impact?
What does the energy price cap mean for your energy bill?
How to calculate your energy bill?
What to do if there are discrepancies with your bill?

What is an energy bill and what is the average energy bill in Great Britain?

An energy bill is a document that details the amount you owe for electricity or gas used during a specific period. With the price cap change in July 2025, it is estimated that the average annual energy bill will be £1,720 in Great Britain from 1st July to 30th September.

Key information about energy bills in Great Britain:

You receive these bills regularly, mostly monthly, but this can depend on your energy provider and the tariff you’re on.
They can be sent via post or electronically if you go paper-free.
If you need help translating your bills, you can use the Priority Services Register – or continue reading for more information about your energy bill.

The key sections of your energy bill explained

Before being able to take greater control over your household energy supply, you need to understand your energy bill. The layout of your energy bill may vary depending on your supplier, but it typically features several key components:

Basic information such as your name and address, the name of your energy supplier and a unique identifier or account number.
Tariff information and details including what tariff you are on for your gas and electricity supply. There are two main types of tariffs, fixed or variable. With a smart meter, you can access other tariffs, like time-of-use tariffs.
Usage breakdown including a record of your gas and electricity meter readings and your energy usage over a specific period. These usage figures will either be estimations, if no meter readings have been submitted, or based on how much has actually been used, if you have a smart meter installed or if a manual meter reading has been submitted for the billing period.
A breakdown of charges such as how much you owe your energy supplier, standing charges (a fixed cost to cover the cost of supplying your property with energy), unit rates set by your energy supplier (how much energy costs per unit) and sometimes how much you’ve previously paid.
Serial numbers for your gas and electricity meters.

Tariff types and your energy bill explained

Want to know about the different types of energy tariffs and how to read your energy bill? Here are the most common ones:

Fixed-rate tariff

A fixed-rate tariff has a ‘fixed’ price that you pay for each unit of energy over a specified period. Fixed tariffs can help with budgeting as you’ll know exactly how much you are paying each month. But if the price of energy drops, you could end up paying more than necessary.

Energy tariffs definitions

Standard variable rate tariff

A standard variable rate tariff is when the unit price of energy changes according to market conditions, typically every three months. Standard variable tariffs are much more flexible than fixed tariffs, but they require you to adapt to changes in the price of gas and electricity, which makes planning ahead more challenging. Your rates could go up or down. If you are on a standard variable tariff, your energy supplier should contact you if your rate changes.

Energy tariffs definitions

Time-of-use tariff

Time-of-use tariffs offer fluctuating electricity rates depending on the time of day when you consume energy. During off-peak periods, such as late at night or in the morning, electricity can be cheaper. By adapting your energy usage habits, you can benefit from these tariffs and save on your energy bills. To be eligible for new time-of-use tariffs, you’ll need to get a smart meter to provide your energy supplier with accurate, regular meter readings.

Time-of-use tariffs

We believe that Octopus Energy is now responsible for Affect Energy customers. Therefore we are connecting you with Octopus Energy who will be responsible for taking your request forward.

We believe that Yu Energy are responsible for Ampower UK customers. Therefore we are connecting you with Yu Energy who will be responsible for taking your request forward.

We believe that British Gas is now responsible for Angelic Energy customers. Therefore we are connecting you with British Gas who will be responsible for taking your request forward.

We believe that SSE is now responsible for Atlantic Energy customers. Therefore we are connecting you with SSE who will be responsible for taking your request forward.

We believe that Nabuh Energy is now responsible for Avid Energy customers. Therefore we are connecting you with Nabuh Energy who will be responsible for taking your request forward.

We believe that Octopus Energy are responsible for Avro Energy customers. Therefore we are connecting you with Octopus Energy who will be responsible for taking your request forward.

We believe that British Gas is now responsible for Beam Energy customers. Therefore we are connecting you with British Gas who will be responsible for taking your request forward.

We believe that British Gas are responsible for Better Energy customers. Therefore we are connecting you with British Gas who will be responsible for taking your request forward.

We believe that OVO Energy are responsible for Boost Energy customers. Therefore we are connecting you with OVO who will be responsible for taking your request forward.

We believe that British Gas is now responsible for Breeze customers. Therefore we are connecting you with British Gas who will be responsible for taking your request forward.

We believe that SSE is now responsible for Brilliant Energy customers. Therefore we are connecting you with SSE who will be responsible for taking your request forward.

We believe that British Gas are responsible for Bristol Energy customers. Therefore we are connecting you with British Gas who will be responsible for taking your request forward.

You can continue your smart meter journey at your supplier's website. They will take your request forward.

We believe that British Gas are responsible for British Gas Evolve customers. Therefore we are connecting you with British Gas who will be responsible for taking your request forward.

We believe that Octopus Energy are responsible for Bulb customers. Therefore we are connecting you with Octopus who will be responsible for taking your request forward.

We believe that SSE are responsible for Cardiff Energy customers. Therefore we are connecting you with SSE who will be responsible for taking your request forward.

We believe that British Gas is now responsible for CitizEn Energy customers. Therefore we are connecting you with British Gas who will be responsible for taking your request forward.

We believe that Shell Energy are responsible for Colorado Energy customers. Therefore we are connecting you with Shell Energy who will be responsible for taking your request forward.

You can continue your smart meter journey at your supplier's website. They will take your request forward.

We believe that Scottish Power is now responsible for Daisy Energy customers. Therefore we are connecting you with Scottish Power who will be responsible for taking your request forward.

You can continue your smart meter journey at your supplier's website. They will take your request forward.

Eon have informed us that Eon Next are responsible for smart meter installations, so you'll be redirected there.

We are redirecting you to the E.ON Next smart meter webpage. You can continue your smart meter journey at their website. They will take your request forward.

If you are a prepay customer you will need to visit Boost Energy at www.boostpower.co.uk/smart-meters. They will be responsible for taking you request forward.

We believe that Octopus Energy is now responsible for Engie customers. Therefore we are connecting you with Octopus Energy who will be responsible for taking your request forward.

We believe that E.ON Next is now responsible for Enstroga customers. Therefore we will connect you with E.ON Next who will be responsible for taking your request forward.

We believe that So Energy is now responsible for ESB customers. Therefore we are connecting you with So Energy who will be responsible for taking your request forward.

We believe that Utilita is now responsible for Eversmart customers. Therefore we are connecting you with Utilita who will be responsible for taking your request forward.

We believe that Scottish Power is now responsible for Extra Energy customers. Therefore we will connect you with Scottish Power who will be responsible for taking your request forward.

We believe that Shell Energy Retail is now responsible for First Utility customers. Therefore we are connecting you with Shell Energy Retail who will be responsible for taking your request forward.

We don't currently have information from your energy supplier regarding their bookings for smart meters, but we will connect you to their website so you can contact them directly.

We believe that British Gas is now responsible for Fosse Energy customers. Therefore we are connecting you with British Gas who will be responsible for taking your request forward.

You can continue your smart meter journey at your supplier's website. They will take your request forward.

We believe that Green Star Energy is now responsible for Future Energy customers. Therefore we are connecting you with Green Star Energy who will be responsible for taking your request forward.

We believe that Octopus Energy is now responsible for Gen4U customers. Therefore we are connecting you with Octopus Energy who will be responsible for taking your request forward.

We don't currently have information from your energy supplier regarding their bookings for smart meters, but we will connect you to their website so you can contact them directly.

We believe that Bulb Energy is now responsible for GnErgy customers. Therefore we will connect you with Bulb who will be responsible for taking your request forward.

We don't currently have information from your energy supplier regarding their bookings for smart meters, but we will connect you to their website so you can contact them directly.

We believe that Shell Energy is now responsible for Goto Energy customers. Therefore we will connect you with Shell energy who will be responsible for taking your request forward.

We believe that British Gas is now responsible for Great North Energy customers. Therefore we are connecting you with British Gas who will be responsible for taking your request forward.

We believe that Shell Energy is now responsible for Green Energy customers. Therefore we will connect you with Shell energy who will be responsible for taking your request forward.

We believe that EDF Energy is now responsible for Green Network Energy customers. Therefore we will connect you with EDF Energy who will be responsible for taking your request forward.

We believe that Octopus Energy is now responsible for Green Star Energy customers. Therefore we are connecting you with Octopus Energy who will be responsible for taking your request forward.

We believe that E.ON Next is now responsible for Hub Energy customers (formerly Gulf Gas and Power). Therefore we will connect you with E.ON Next who will be responsible for taking your request forward.

If you would like a smart meter installed, please get in touch with Homeshift using the contact number on your latest energy bill.

We believe that E.ON Next is now responsible for Hub Energy customers. Therefore we will connect you with E.ON Next who will be responsible for taking your request forward.

We believe that E.ON Next is now responsible for Igloo Energy customers. Therefore we will connect you with E.ON Next who will be responsible for taking your request forward.

We believe that Octopus Energy is now responsible for Iresa customers. Therefore we are connecting you with Octopus Energy who will be responsible for taking your request forward.

We believe that EDF Energy is now responsible for iSupply Energy customers. Therefore we are connecting you with EDF Energy who will be responsible for taking your request forward.

We don't currently have information from your energy supplier regarding their bookings for smart meters, but we will connect you to their website so you can contact them directly.

We believe that OVO Energy is now responsible for Lumo customers. Therefore we are connecting you with OVO Energy who will be responsible for taking your request forward.

We don't currently have information from your energy supplier regarding their bookings for smart meters, but we will connect you to their website so you can contact them directly.

We believe that British Gas is now responsible for MoneyPlus Energy customers. Therefore we will connect you with British Gas who will be responsible for taking your request forward.

We believe that British Gas is now responsible for Nabuh Energy customers. Therefore we will connect you with British Gas who will be responsible for taking your request forward.

We believe that British Gas is now responsible for Neon Reef Energy customers. Therefore we will connect you with British Gas who will be responsible for taking your request forward.

We believe that E.ON is now responsible for Npower Select customers. Therefore we will connect you with E.ON who will be responsible for taking your request forward.

We believe that E.ON Next is now responsible for Npower Select customers. Therefore we will connect you with E.ON Next who will be responsible for taking your request forward.

We believe that Utilita are responsible for Omni Energy customers. Therefore we are connecting you to Utilita who will be responsible for taking your request forward.

We beleive that Scottish Power is now responsible for Orbit Energy customers. Therefore we will connect you with Scottish Power who will be responsible with taking your request forward.

We believe that Utilita is now responsible for Our Power customers. Therefore we are connecting you with Utilita who will be responsible for taking your request forward.

We believe that British Gas is now responsible for People's Energy customers. Therefore we will connect you with British Gas who will be responsible for taking your request forward.

We believe that British Gas is now responsible for PFP Energy customers. Therefore we will connect you with British Gas who will be responsible for taking your request forward.

We believe that E.ON Next is now responsible for Powershop customers. Therefore we will connect you with E.ON Next who will be responsible for taking your request forward.

We believe that Shell Energy is now responsible for Pure Planet customers. Therefore we will connect you with Shell Energy who will be responsible for taking your request forward.

We believe that Octopus Energy is now responsible for Qwest Energy customers. Therefore we are connecting you with Octopus Energy who will be responsible for taking your request forward.

We believe that British Gas is now responsible for Ram Energy customers. Therefore we are connecting you with British Gas who will be responsible for taking your request forward.

We believe that British Gas is now responsible for Rebel Energy customers. Therefore we will connect you with British Gas who will be responsible for taking your request forward.

We believe that British Gas is now responsible for Robin Hood Energy customers. Therefore we will connect you with British Gas who will be responsible for taking your request forward.

You can continue your smart meter journey at your supplier's website. They will take your request forward.

Scottish Gas have told us that British Gas is responsible for providing smart meters on their behalf. Therefore we are connecting you with British Gas who will be responsible for taking your request forward.

Scottish Hydro have told us that SSE is responsible for providing smart meters on their behalf. Therefore we are connecting you with SSE who will be responsible for taking your request forward.

We believe that Octopus Energy is now responsible for Shell Energy customers. Therefore we are connecting you with Octopus Energy who will be responsible for taking your request forward. If you are a former Shell customer and haven't seen an email from Octopus, please get in touch with them.

We believe that British Gas is now responsible for Simplicity Energy customers. Therefore we will connect you with British Gas who will be responsible for taking your request forward.

We believe that SSE is now responsible for Spark Energy customers. Therefore we will connect you with SSE who will be responsible for taking your request forward.

We believe that British Gas is now responsible for Southend Energy customers. Therefore we are connecting you with British Gas who will be responsible for taking your request forward.

We believe that Nabuh Energy is now responsible for Snowdrop Energy customers. Therefore we are connecting you with Nabuh Energy who will be responsible for taking your request forward.

We believe that British Gas is now responsible for Social Energy customers. Therefore we will connect you with British Gas who will be responsible for taking your request forward.

We don't currently have information from your energy supplier regarding their bookings for smart meters, but we will connect you to their website so you can contact them directly.

We believe that EDF are responsible for Solarplicity customers. Therefore we are connecting you with EDF who will be responsible for taking your request forward.

We believe that OVO energy are responsible for SSE customers. Therefore we are connecting you with OVO who will be responsible for taking your request forward.

Swalec have told us that SSE is responsible for providing smart meters on their behalf. Therefore we are connecting you with SSE who will be responsible for taking your request forward.

Symbio Energy have told us that E.ON NEXT is responsible for providing smart meters on their behalf. Therefore we will connect you with E.ON NEXT who will be responsible for taking your request forward.

We believe that British Gas is now responsible for The Leccy customers. Therefore we are connecting you with British Gas who will be responsible for taking your request forward.

We believe that British Gas are responsible for Together Energy customers. Therefore we are connecting you with British Gas who will be responsible for taking your request forward.

We believe that Scottish Power is now responsible for Tonik Energy customers. Therefore we are connecting you with Scottish Power who will be responsible for taking your request forward.

We believe that EDF Energy are responsible for Toto Energy customers. Therefore we are connecting you with EDF Energy who will be responsible for taking your request forward.

We believe that Octopus Energy are responsible for UKEIH customers. Therefore we are connecting you with Octopus Energy who will be responsible for taking your request forward.

We believe that Shell Energy Retail is now responsible for Usio Energy customers. Therefore we are connecting you with Shell Energy Retail who will be responsible for taking your request forward.

We believe that EDF Energy is now responsible for Utility Point customers. Therefore we will connect you with EDF Energy who will be responsible for taking your request forward.

We believe that E.ON are responsible for Wasp Energy customers. Therefore we are connecting you with E.ON who will be responsible for taking your request forward.

We believe that British Gas is now responsible for White Rose Energy customers. Therefore we are connecting you with British Gas who will be responsible for taking your request forward.

We believe that E.ON are responsible for Wigan Warriors Energy customers. Therefore we are connecting you with E.ON who will be responsible for taking your request forward.

We beleive that Scottish Power is now responsible for Yorkshire Energy customers. Therefore we are connecting you with Scottish Power who will be responsible for taking your request forward.

We believe that British Gas is now responsible for Your Energy Sussex customers. Therefore we are connecting you with British Gas who will be responsible for taking your request forward.

We believe that British Gas is now responsible for Zebra Power customers. Therefore we are connecting you with British Gas who will be responsible for taking your request forward.

We believe that EDF is now responsible for Zog Energy customers. Therefore we are connecting you with EDF who will be responsible for taking your request forward.

What does the energy price cap mean for your energy bill?

The energy price cap is set by Ofgem, Great Britain’s independent energy regulator. The price cap puts a limit on how much your energy supplier can charge you for each unit of gas and electricity.

What does the energy price cap mean?

The price cap protects consumers on default or standard variable tariffs by ensuring they are not overcharged.

What is the maximum energy bill cap?

It is important to note that the price cap is reviewed and updated quarterly by Ofgem in response to changes to the cost of wholesale energy. It is also a cap on the rate paid per unit of energy, not on the total energy bill. So, there is no fixed maximum energy price cap.

For more information about the current price cap, visit our price cap page or Ofgem’s website.

Understanding energy usage: How to calculate my energy bill

The charges on your energy bill from your supplier are based on your electricity or gas meter readings. If no readings were submitted, the bill will be based on estimates. The number of units used is multiplied by the unit rate you are being charged.

If you’re asking, “how can I calculate my energy bill” or “how much will my energy bill be”, here’s how to calculate the cost

Start by checking the number of energy units you’ve used (measured in kWh). This information will be listed on your energy bill.
Next, look for the agreed unit rate on your bill; this is the price you pay per unit of energy.
Multiply the energy units used by your agreed unit rate. The result will give you the total energy cost for the period.

The formula is:

Energy units used (kWh) X your agreed unit rate = energy cost

All this information can be found directly on your energy bill, allowing you to easily check how much energy you have used.

Your supplier may also include additional fees, such as standing charges or other services, to your total energy bill.

If you are interested in working out the running costs of individual appliances, check out our guide on appliance running costs or use our energy cost calculator.

Work out my energy bill: What to do if there are discrepancies?

If your energy bill is not in line with what you were expecting, it’s a good idea to double check it, to understand the charges and how much you have to pay. If you want to double check and you’re wondering how to read your energy bill to ensure that it is accurate, follow these steps:

Check that the right home address has been listed and no mistakes have been made.
Check if the usage data is estimated – this can result in an unexpected bill. One resolution to this is sending accurate meter readings through a smart meter.
Check the tariffs and rates listed on your energy bill.
Compare your energy bill with a previous bill, to see if this is in line with what you would normally spend at this time of year.
If everything else is as expected, and you still think your bill does not look right, check that the meter serial numbers on your energy bill match the serial numbers on your actual gas and electricity meters.
Get a smart meter. They send meter readings directly to your energy supplier, eliminating the need for estimated bills and providing peace of mind that your bills are accurate. Additionally, its in-home display allows you to monitor your energy usage in near real-time, offering greater accuracy and control over your energy use.