How to Read and Check an Energy Bill
A line-by-line guide to what is actually on your gas and electricity bill, and how to spot the errors that cost households money.
Why it is worth checking
Energy bills are dense, but most of the information on them exists for a reason: it lets you check that you are being charged correctly. Estimated readings, wrong meter serial numbers and incorrect tariff rates all happen, and they are far easier to fix quickly than months later. Knowing what each section means turns a confusing document into a useful check.
The identifiers: MPAN and MPRN
Every bill has a unique reference for your supply point. Electricity bills show an MPAN (Meter Point Administration Number), often called an ‘S number’, usually a long string that includes a shorter core number. Gas bills show an MPRN (Meter Point Reference Number). These identify your specific property connection, not you as a customer, so they stay the same even if you switch supplier. If you ever query a bill or switch, having this number ready speeds things up. Check it matches the number physically printed on or near your meter.
Meter readings: actual versus estimated
Bills usually state whether a reading is ‘actual’ (taken from the meter itself, either by you, a smart meter, or an engineer) or ‘estimated’ (a guess based on past usage, marked with an E). Estimated readings are the single biggest cause of bill shock, because if your usage pattern changes, such as a colder winter or a new appliance, the estimate can be badly wrong. Always compare the reading on the bill to the actual number showing on your meter. If it is estimated and wrong, submit a real reading through your supplier’s website or app so the next bill corrects itself.
Understanding units: kWh, not units on the dial
What you are charged for is kilowatt hours (kWh), a measure of energy used, not the raw number shown on the meter dial. Electricity meters generally show kWh directly. Gas meters are different: older meters measure in imperial units (cubic feet) or metric units (cubic metres), and the supplier converts this into kWh using a formula that accounts for the calorific value of gas and a volume correction factor. You do not need to do this maths yourself, but it explains why your gas kWh figure will not match the number on the meter dial itself, and it is normal.
Unit rates and standing charges
Each bill splits the cost into a unit rate (pence per kWh, the cost of the energy you actually use) and a standing charge (a fixed daily amount charged regardless of use, covering the cost of supplying the connection). Both figures should be shown clearly, usually per fuel. Check these against the tariff you signed up to or were placed on, which your supplier should have confirmed by email or letter when it started. If you are on a variable tariff, rates can change when the regulator’s price cap is updated, so compare the figure on your bill to what is currently published rather than relying on memory of what you were quoted originally.
VAT and total cost
Domestic energy in the UK carries a reduced rate of VAT, and this should be itemised separately near the total. If a bill shows VAT at a different rate, or missing entirely, that is worth querying.
Direct debit and your account balance
Most people pay energy by fixed monthly direct debit, calculated by the supplier to spread an estimated annual cost evenly, rather than paying for exactly what they use each month. This means your account can build up a credit balance in warmer months and run down in colder ones. The bill or online account should show your current balance and how it was calculated. A very large credit balance sitting with your supplier for a long period is worth challenging; ask for the direct debit to be reviewed and reduced, or for a partial refund, particularly if your usage has been fairly stable and predictable.
Comparing bill periods
Good bills show a graph or table of recent usage by month, letting you compare periods and fuels. Look for unexplained jumps. A sudden spike might mean an estimated reading has corrected itself, a new appliance, more time at home, or, occasionally, a fault such as a stuck meter or an issue with the property’s wiring or pipework. A sudden drop to near zero on an occupied property is also worth investigating, since it may indicate a meter fault rather than genuine savings.
What to do if something looks wrong
If a reading, rate or charge looks incorrect, contact your supplier’s customer service team with your account number, the MPAN or MPRN, and a photo of your actual meter reading with the date. Ask for the bill to be corrected and reissued. If you cannot resolve it directly, every supplier has an internal complaints process, and if that does not fix things within the standard timeframe, you can escalate to the free Energy Ombudsman. Citizens Advice and MoneyHelper both offer free, independent guidance if you are unsure whether a bill or a supplier’s response is reasonable.
The habit worth building
Submitting a genuine meter reading regularly, or having a working smart meter that does this automatically, is the single most effective habit for keeping bills accurate. It removes the guesswork that estimated billing depends on and makes any dispute far quicker to resolve, because you have your own record of actual usage over time.