Energy bills explained

Energy bills explained

YouGov research on behalf of uSwitch found 75% of people find energy bills confusing, and only 4 in 10 could understand the calculations on their bill.

Watch our short video on how to get the info off your bill that you need to switch, and get helpful inisght from our Energy Expert, Tom Lyons.

Or get help your reading British Gas, EDF Energy, E.ON, npower, ScottishPower, SSE or Ovo bill below with our handy bill breakdowns.

Energy bills explained video

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Help me read my bill

We've put together a sample of the most popular suppliers' gas and electricity bills. These energy bill breakdowns might not look exactly like yours — because you may pay differently than the sample or only have one fuel — but the bill layout for your supplier should generally be the same, making it easy to spot key items like your annual consumption, plan name, cancellation fee info and unit rate.

The big six energy bill breakdowns

British Gas energy bill sample (dual fuel, pay on receipt)

EDF Energy bill sample (dual fuel, direct debit)

E.ON Energy bill sample (dual fuel, monthly direct debit)

npower bill sample (dual fuel, monthly direct debit)

ScottishPower bill sample (dual fuel, monthly direct debit)

SSE bill sample (single fuel, direct debit)

Small suppliers energy bill breakdown

OVO bill sample (dual fuel, monthly direct debit)

Still have questions about your bill? Check our Energy bill jargon buster section for definitions for everything from "calorific value" to "NSC".

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Energy bills jargon buster

Our glossary lists all the terms you're likely to find, either on your bills or across our site. Simply click on the term you need explained and we'll tell you what it all means.

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Account number

Your account number is how you reference your specific account when contacting your current supplier. This number will be printed on your bill and may also be called your customer number.

Calorific Value (CV)

'Calorific Value' (CV) is a scientific term used to describe how much heat is generated when a known volume of gas is completely burned away.

Gas passing through the National Grid has a CV of 37.5MH/m3 to 43.0MJ/m3, but the CV for your specific area should be displayed on your gas bill.

Put simply - the CV measures how 'useful' your gas is, so your supplier can charge you based on the quality of the gas that is supplied to you.

For more information on calorific values and how they're calculated, please refer to the National Grid website.


If you have any discounts such as dual fuel applied to your energy bills, it will be marked clearly near the final total.

In an effort to make your energy costs clearer, Ofgem recently placed limitations on the kinds of discounts suppliers can offer. Therefore, the most common discounts are dual fuel discounts and direct debit discounts.

To read more about the recent changes Ofgem have enacted, read our Retail Market Review guide.

Dual Fuel

Dual fuel is where you receive your gas and your electricity supply from the same energy company. You can often receive a discount from your energy supplier by doing this.

Read more about dual fuel.

Economy 7

Economy 7 is a type of electricity tariff that uses different prices for the electricity you use during the day and the electricity you use during the night.

Typically the electricity you use at night will cost you less than electricity used during the day. With Economy 7, the 'night' usually refers to the early hours, between around 1am to 8am, but these hours can vary between suppliers. Read more about Economy 7.

Economy 10

This structure gives you three off-peak hours in the afternoon, two in the evening and five hours overnight. The designated hours will change between suppliers. Unfortunately we cannot support economy 10 switching on uSwitch.

Read more about economy 10 tariffs here.

Estimated (E) or actual (A) readings

If your meter reading has been estimated that means your energy supplier has assumed your usage for the bill period based on your past consumption.

If they don't have information on your previous usage (you just moved or just switched), they will use national average figures to estimate your consumption and your therefore your costs.

If you have submitted a reading or your supplier has sent someone to take a reading, then this will appear as "actual" on your bill.

Where this info appears on your bill will vary by supplier. Check the sample bill links above for help.

Tip: To ensure your bills are as accurate as possible — and to avoid under- or overpaying for your energy — it is best to submit your own meter readings.

If you're not sure how to take a meter reading, read our guide on taking a gas or electricity meter reading

Fixed Monthly Direct Debit (MDD)

If you hold a monthly direct debit with your supplier, then you will pay a set amount to your supplier every month. However this does not mean that unit rate is fixed, as is the case with fixed price plans.

Your energy supplier needs to give you notice if they intend to change the amount of the monthly direct debit, which may occur during seasons change and your usage goes up or down.

How to convert units to kWh

On your energy bill, your gas units will be converted to kilowatt hours. Please note that the Calorific Value will change depending on your area - so please check your bill for the correct figure.

Use the following formula to convert units to kWh:

Total units used x metric conversion factor (2.83) x volume correction factor (1.02264) x calorific value /kilowatt hour conversion factor (3.6).

This works for meters that record hundreds of cubic feet where your gas meter shows 'ft3' next to the reading. If your meter measures in cubic meters with an 'm3' next to the reading, then go through the same sum while removing the metric conversion factor of 2.83.

Example for meter that records hundreds of cubic feet:

1 unit x 2.83 x 1.02264 x 39.1 / 3.6 = 31.43 kWh

IGT Network/charges

IGT stands for 'Independent Gas Transporter'. If your home is supplied by an Independent Gas Transporter Network, it means that it is not connected to the National Grid, which supplies most of the UK's home's with gas.

If your MPRN number is 10 digits long and begins with 74 or 75 then you are supplied by an IGT.

It used to be that IGT homes had an extra charge on their bills associated with this supply method, but recently this cost has been absorbed by the big six suppliers — though some smaller suppliers may still charge.

If you are being charged as an IGT home, you can call your supplier to discuss your options, and remember you can still switch energy if you are on an IGT supply.

Kilowatt hours (kWh)

A kilowatt hour is the standard measurement of energy that your energy supplier will use to bill you. A kilowatt hour refers to a person using 1,000 watts of electricity for 1 hour. Your prices will be set per kilowatt hour (kWh) of energy you use.

Loyalty points

Loyalty points will only apply to certain tariffs, and can come in different forms, such as Sainsbury's Nectar Points and Tesco Clubcard points. These points can be earned on energy bills with suppliers that have a commercial arrangement with specific supermarkets. The number of points you've accrued should be displayed clearly on your bill.

Meter point administration number (MPAN)

Your meter point administration number will often be referred to as your MPAN or your supply number. It can also be referred to as your 'S' number. This number is assigned to the electricity meter at your property to identify it, and can be found on your electricity bill. It is displayed in a very specific format as pictured below:

Supply number

If you can't find your MPAN or supply number, use our energy bill breakdown above for your supplier to locate it.

Meter point reference number (MPRN)

Your meter point reference number will often be referred to as your MPRN number. This number is assigned to the gas meter at your property, and can be between 6 and 10 digits long.

On your bill this number may be referred to as an 'M' number, but if you can't find it you can use our energy bill breakdown above for your supplier to locate it.

Metric conversion factor

An imperial to metric conversion factor of 2.83 is used in the calculation to convert units into kilowatt hours (kWh).


MPRN is the abbreviation for meter point reference number and MPAN is the abbreviation for meter point administration number. Please see above for further details on what this means.

NSC - No Standing Charge

If you are on an older energy plan, your bill may includes the abbreviation 'NSC' or the words 'No Standing Charge', which means your supplier does not apply a fixed daily charge to your plan.

In an effort to make your energy costs clearer, Ofgem banned "No Standing Charge" plans, requiring that all suppliers charge a daily rate. This rate is not set by Ofgem, so you can still get an NSC plan of sorts by finding a supplier with a "charge" of zero for the standing charge fee. Just be sure to check the kWh rate is also competitive.

To find your standing charge amount on your bill, use the energy bill breakdown link above for your supplier.

Plan/tariff name

The name of your energy plan identifies which tariff you are on, which in turn dictates the prices you are charged.

Although Ofgem has worked to reduce the "clutter" of plans on the market, there are hundreds of different plans available, and naming conventions will differ between suppliers.

You need to know your plan name in order to switch. You can find this info on your bill, and you can use our energy bill breakdown info above to quickly locate it for your supplier's bill.

Standing charges

All energy plans now include a standing charge — this has changed recently as part of Ofgem's efforts to simplify the market.

A standing charge is a fixed daily charge meant to cover the costs of keeping your home connected to the grid. The idea is that by separating out this daily non-energy-consumption related charge from your unit rate, what you are charged for is made more clear.

You can still effectively get a "no standing charge" plan by looking for a supplier that charges zero for their standing charge.

To find out what your standing charge is, check your bill. If you have trouble locating it on your bill, use our energy bill breakdown links at the top of the page.

Standing Order

If you hold a standing order with your energy supplier, you have arranged for a fixed amount to be sent from your bank account to pay your energy bill as often as necessary.

You have control of this payment method, so your energy supplier cannot change the payments at their end, even with your permission.

Supply number

Your supply number can also be referred to as your MPAN or electricity meter point administration number.


Tiered energy pricing is yet another tactic that Ofgem has done away with to help clarify your costs.

Any plan introduced after April 2014 should not have a tiered pricing scheme. If you check your bill and see two different rates, this could be two things: you're on a variable rate plan and your supplier implemented a price change; or you are on an economy 7 plan


Although your gas will be charged according to kilowatt hours (kWh) used, your gas will initially be measured in units. This is then converted to kilowatt hours on your bill using a standard formula. Find out how to convert kWh's into units.

Variable Direct Debit (VDD)

If you have a variable direct debit set up with your energy supplier, then you are giving them control over the direct debit. They will amend the amount taken each month to pay off the outstanding bill, and they do not have to give you notice before changing the amount.


VAT will be charged on top of your total bill at a standard rate of 5% instead of the usual 20%. It is important to note that your gas and electricity bills will show all unit prices before VAT, whereas uSwitch is required to display all unit prices with VAT included. This allows us to make the most accurate and relevant comparison for you.

Volume correction factor

The volume correction factor of 1.02264 takes into account the changes in the volume of gas based on temperature and pressure.

Back to top of page

Read more…

  • Utility Bills Your utility bills may not make pleasant reading, but they contain vital information
  • Annual Energy Statements Your annual energy statement holds the secret to saving money on your bills
  • Household Bills Household bills can be tricky to decipher, but understanding what your reading is the key to saving money
    • Read the Transcript

      Energy bills can be hard to make sense of. Our research shows that as many as 75% of us find them confusing , and it's really tempting just to shove them in a draw and forget about them. But it's important to take a good look at them when you get them, and it doesn't need to be hard to do. You just need to know what to look out for.

      Is it an estimated bill?

      You can find this out by looking at the summary section which is usually on the first page of your bill. If there's an 'e' or 'estimated' next to this amount it means your bill is based on estimated meter readings, rather than actual ones.

      If this is the case you should take a meter reading and send it to your supplier to ensure you get fully accurate bills.

      Has your last payment been received?

      The summary section will also tell you how much your last payment was for and when it was received.

      Full breakdown of your bill

      Is your bill any different to normal? The full breakdown of your bill is usually on the second page and will show you your tariff name and how much you pay for electricity and gas per kWh.

      If any of these details have changed you should think about the impact it has on your bill. For example, if your tariff name has changed it could mean that an old deal your on has expired or that unit rates have gone up. This could lead to higher bills and it could mean it's time to come to uSwitch and make sure you're still on the best deal for you.

      What other information do you need if you want to switch supplier?

      Next let's look at the bits of information on your bill if you want to switch energy supplier. Your supplier's name, your electricity supply number of MPAN, the name of the tariff you're on, your gas meter number or MPRN, and the amount of electricity and gas you've used in kWh.

      Annual energy statement

      Finally keep you eyes peeled for your annual energy statement. Your supplier is now required to send you one of these and it will tell you the name of the tariff you're on, how much energy you've used over the last year, and how much your energy will cost you over the coming year; everything you'll need to make sure you're on the absolute best deal.

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