Page last updated on 24th April 2026
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 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 October 2025, it is estimated that the average annual energy bill will be £1,755 in Great Britain from 1st October to 31st December.
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.
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.
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.
Understanding your energy bill
Learn more about your energy bill with the visual below. For a full description of the image text you can click on 'continue reading'.
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.
If something doesn’t look right, don’t hesitate to reach out to your energy supplier and they can explain or rectify the issue. To escalate issues, please refer to our guide on how to make a complaint.
Learning how to read your energy bill may take a bit of getting used to, but it can potentially help you get control over your energy bills and support you make savings. With our nation’s goal of achieving net zero by 2050, understanding your energy usage could help you find ways to reduce your carbon footprint and save money.
You may also be interested in...
