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Energy bills explained

Find out how to read your OVO energy bill – and what all the different bits mean.

How do I read my OVO energy bill? What does it cover?

There’s a lot of info on your energy bill, which can be pretty confusing. That’s why we’ve put together this jargon-busting FAQ to reveal what it all means.

Account number

Your unique OVO Energy Account number.


To control your account online in My OVO, you can log in with this ID (or you can use your email address).

Statement date and number

This is the unique number of your energy statement on our systems. Plus the date we send your statement out. It’s useful to have these to hand if you ever call us about a specific statement.

Cheaper Tariff Messaging

This tells you if you could be on another cheaper tariff with OVO. It shows you the one that’s most similar – and the cheapest overall.

Tariff info

Tells you all about your tariff. It’ll include everything from the plan name and how you pay, to how much energy you use. You can use this info to compare plans from OVO and any other supplier.

Charging period 

This shows the start and end dates for the billing period that’s covered by this statement.

Charge per fuel

Tells you how much you’ve paid for electricity and/or gas during the statement period.

OVO Interest Reward

Our Interest Reward that we give on credit balances.

Self Service Reward

You’ll see this reward if you’re using an online-only plan.


Like all energy suppliers, we add VAT to your total.

Direct Debit

The date and amount of your direct debit payment.

Your balance

The total amount that you owe us or we owe you.

Electricity used


Your Meter Point Administration Number (MPAN) is the unique identifying number for your electricity, so it doesn’t change if you switch suppliers. 

Supply Number

Shows the MPAN for your supply (they’re the numbers in the 3 boxes at the bottom).

Meter Serial Number

Your Meter Serial Number (MSN) is often printed on a sticker or engraved onto your meter. It should match the number shown on your statement.

Meter readings

  • Shows the meter readings we’ve used and the dates they were taken. If you have a traditional meter and send us regular readings, this is what you’ll see most of the time:
  • The first one is the estimated reading on which we based your previous bill.
  • The bottom one is the estimated reading we’re using for this bill.
  • If you’ve given us a reading during the billing period, it will appear in between.
  • If you’ve given us more than one reading, we’ll show the most recent one.

Why are estimated readings used when my meter reading was submitted on time?

We use estimated readings because we need to bill you for the amount of energy you’ve used up to the exact date of your statement. The only time that estimates wouldn’t be used is when you submit your meter reading on exactly the same day that your statement is generated. 

For the estimated readings, our system works out how much energy you used each day between the first estimated reading and your own meter reading. Then it calculates what reading you would have reached on the day we issue your statement, if you’d carried on using gas or electricity at exactly the same rate each day.
So, for instance:

  • We issue a gas statement for the period ending 1 October at a reading of 8,000.
  • On 25 October you give us a reading of 8,025, so you’ve used 1 unit a day over those 25 days.
  • Your next statement covers the period up to 31 October, so for those extra 6 days we add on another 6 units.

If you’ve got a smart meter and you chose for it to send us meter readings ‘once a month’ or ‘once a day’, we’ll only base your statement on estimated readings if we’ve lost communication with your smart meter. If you think your smart meter might have lost connection, you can follow our smart meter troubleshooting steps to find out how to get everything working again.    

Unit rate, price per kWh

The cost of your energy per kilowatt hour and how many kWh you’ve used in this billing period. For gas meters, you’ll also see the meter units you’ve used, which are then converted into kWh to make them easy to compare.

Total charges

The total cost for the electricity and/or gas used before VAT is added.

Standing charge

How much you pay for us to supply energy to your home for this billing period. It’s a fixed daily price multiplied by the number of days.

Gas used


Gas usage

This details your Meter Point Reference Number (MPRN), Meter Serial Number (MSN), your tariff, charge period, the meter readings we used and the cost of your gas.

Explaining your gas statement

Explains in detail how we work out how much gas you use. All suppliers use the same formula.


Understanding your gas formula

Meter units

The number of units used between the two meter readings.

Volume conversion factor

This is different depending on the type of meter you have:

  • Imperial - 2.83
  • Metric - 1

Volume correction

This corrects the volume of gas to account for temperature and pressure, this is a regulated figure. Calorific value This figure is then multiplied by the calorific value of the gas which is a measure of the available heat energy. Calorific values vary and the figure is quoted on your bill.

Convert to kWhs

Again, this factor is regulated and is the figure used to convert to kWh.

kWhs used

The actual number of kWhs used during the billing period, which is then used to calculate how much money your energy usage costs.


If we have more than 1 reading during the statement period

We’ll take the number of gas meter units used between the two meter readings, then follow the calculation above to work out how many kWhs you’ve used. We’ll do this calculation for as many readings we have during the statement period.


For example:

  1. If you gave a reading on the 15th of the month and you’d used 38 units of gas we will do this calculation using 38 units of gas.

  2. Then if you gave a reading on the 31st of the month and you’d used 26 units we’ll use this figure to calculate the number of kWhs used.

  3. We’ll then round both consumption figures, add them together and then round them once more.

If you’ve had a new meter fitted during your statement period

If you’ve had a new meter fitted, it’s likely to change from an older imperial meter that measures in cubic feet to a newer metric meter, that measures in cubic metres. To work out how many kWhs you’ve used during this period we’ll need to apply a different Volume Conversion Factor to the calculation. We’ll follow this calculation for both types of meters.


The first calculation will be meter units used whilst the meter was metric and one will include the meter units used whilst the meter was imperial. They will both then be rounded, summed and rounded once more to calculate your usage for this period.

The Calorific value varies throughout the year and may be different per meter reading.


Send us your meter readings

Lets you know how to submit meter readings to keep your statements super-accurate.

Gas emergency

Explains what to do and who to call if you ever smell gas.  

Your gas distribution

Explains how your gas is supplied.

Contacting your local electricity network

If your power goes down, or you have to move the meter or upgrade your supply, you need to contact your Local Network Operator. This section gives you their contact details.

Our energy sources

Our energy comes from a variety of sources, like natural gas, and this section shows you the percentages of each compared to the national average.

Impartial advice

Points you in the right direction for free and independent advice on energy and your money.


Should you ever want to make a complaint about OVO, this section tells you exactly what to do.

Looking at a statement issued before July 2017?

Then it will also include the Tariff Comparison Rate:

Tariff Comparison Rate

The Tariff Comparison Rate (TCR) was an energy industry standard designed to help you compare your energy plan with other providers. It included your plan name, how you paid, when it ended, and your estimated annual consumption (which means how much energy we expected you to use in a year). It also showed the exit fees you’d have to pay if you left before your plan ended. It was only used for comparing average consumption.

What is a standing charge?

A standing charge is a daily fixed charge that goes towards the cost of supplying energy to your address. It includes the cost of the pipes and power lines, and maintenance of your meters. You pay your standing charge no matter how much energy you use – even if you have a smart meter.

Why do you charge a standing charge? 

Because we use a standing charge, we don’t have to use structured unit prices like other suppliers do. We believe our way is honest, transparent and much simpler.

What is a unit rate?

A unit rate is what we charge for each unit of energy (kWh). Each plan has different unit rates, and you can find yours like this: 

  • Look on the welcome letter we sent you just after sign-up.
  • Or check in My OVO:
  1. Log into My OVO.
  2. Click ‘Check my details’ under ‘My Profile’.
  3. Under ‘My plan’, look for the number that comes before ‘p/kWh’.

You can also check out our unit rate table this also includes our standing charges. However, if you fixed your prices a while ago, these rates may not be the same as the ones you’re paying. That’s why it’s better to check your welcome letter or My OVO.

Why do you charge a unit rate?  

It pays for your energy. A little also goes towards the cost of supplying services to your address and the maintenance of your meters (most, however, is paid through your standing charge).

What is a Tariff Comparison Rate?

A Tariff Comparison Rate (TCR) was once used to help you compare OVO prices against other suppliers’ offers. It was introduced by Ofgem, then withdrawn in 2017.
You would have seen it as a section on your bill showing a breakdown of what the average medium user spends based on the plan you chose.

Does OVO have a tariff without a standing charge? 

No, unfortunately not. All our plans have a standing charge, so we don’t have to use structured unit prices like other suppliers do. 

Do your standing charges change?

Since the cost of supplying the energy to your home goes up and down, your standing charges go up and down too. Here’s our historical standing charge data.

Related FAQs


Find out everything you need to know about Direct Debits – and every other way to pay.

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Debt and energy assistance

Find out ‘what’ to do and ‘where’ to get support when you can’t pay your bills.


Find out how to get one if your balance is too high.

Annual statements

Discover what they are – and why we send them.

Winter Fuel Allowance

Discover what it is, how to claim it – and lots of other helpful stuff.

OVO Interest Reward

OVO Interest Reward is where we pay you interest on your credit balances.

The Warm Home Discount (WHD)

Find out what it is, how you get it – and everything in between.

Cold Weather Payments

Find out what they are, how you qualify – and everything else you need to know.

Statement history

Find out how to get a copy of your statement – and how to ‘go paperless’.


From what they are and how to apply, to everything else you need to know.

Our Direct Debit reviews explained

Everything you need to know about how they work and why they’re important.

How to set up or change your Direct Debit

Here’s everything you need to know.

How do Direct Debits work?

See how we calculate your Direct Debit amount and why it might change over the course of your contract.

Self Service Reward

Information on our soon-to-end Self-Service Reward payments for existing OVO members.

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