ELECTRICITY
First five numbers
On a single-rate digital electricity meter, Citizens Advice says to write down the first 5 numbers from left to right and ignore any red numbers.
Check your meter
IGNOREthe red numbers
- Read left to right
- Skip red digits
- Note both rates
- Accurate readings, accurate bills
Without regular readings, your supplier estimates what you have used, and that can make a bill too high or too low. Most meters follow a few simple rules: read left to right, ignore the red numbers, and note both rates if you have two.
Updated
THE SHORT ANSWER
Read it often,
send it in.
Your supplier needs regular readings.
Without them, it estimates your use.
GAS
Metric or imperial
On a digital metric gas meter, note the first 5 numbers before the decimal point. On an imperial one, note the first 4 and ignore the 2 red numbers.
Step by step
SMART
Usually automatic
Smart meters normally send readings to your supplier automatically. You may still need to read one after switching supplier or if it stops connecting.
See the numbersA QUICK METER CHECK
What kind of
meter is it?
Pick the meter that looks like yours to see how to read it. The bar shows how fiddly that type is to read.
Based on Citizens Advice guides to reading gas, electricity and smart meters. Check your supplier's guidance if your meter looks different.
TWO NUMBERS WORTH KNOWING
Most meters are smart,
and old bills have limits.
One figure on the smart meter rollout,
one on how far back a catch-up bill can reach.
72%
Share of meters that are smart or advanced, June 2026
Government figures show 42 million smart and advanced meters out of 57.5 million in Great Britain's homes and small businesses at the end of June 2026. 92% of smart meters were working in smart mode.
SMART METERS · DESNZ
12 months
Furthest back a supplier can usually bill
Since 2018, Ofgem rules have stopped suppliers back-billing domestic customers for energy used more than 12 months ago, unless the customer acted obstructively, such as blocking access to the meter.
BACK-BILLING · OFGEM
Before the ban, Ofgem said the typical domestic back-bill in its October 2016 to March 2017 sample was £1,160, and the median back-bill covered 24 months.
READING A DIAL METER
One dial
at a time.
Dials are the trickiest meters to read. These steps follow the Citizens Advice method for electricity dials.
Read left to right
Take the first 5 dials for electricity, or the first 4 for gas, ignoring red dials and any marked 1/10.
Take the lower number
If a pointer sits between two numbers, write the lower one. If it sits between 9 and 0, write 9.
Underline exact hits
If a pointer sits right on a number, write it down and underline it.
Check the next dial
For an underlined number, look at the dial to its right. If that pointer is between 9 and 0, reduce the underlined number by 1.
WHEN BILLS CATCH UP
Estimates can
come back to bite.
A back-bill happens when a supplier recalculates what you owe, often after a real reading shows earlier estimates were too low. The Energy Ombudsman lists causes such as meters left unread, faulty early smart meters and readings rejected by a supplier's systems.
Ofgem's rules mean suppliers cannot back-bill domestic or microbusiness customers for energy used more than 12 months before the bill, unless it was billed before. If a dispute is not sorted within 8 weeks, or you get a deadlock letter, you can go to the Energy Ombudsman.
Questions
Questions people ask
Which numbers do I ignore on my meter?
On electricity meters, ignore red numbers and red dials. On metric gas meters, ignore numbers after the decimal point; on imperial gas meters, ignore the 2 red numbers.
What if a dial pointer is between 9 and 0?
Write 9. If a pointer is between any other two numbers, write the lower one, according to Citizens Advice.
Do I need to read a smart meter?
Usually not, as smart meters normally send readings automatically. You may need to after switching supplier, or if a new supplier cannot connect to an older smart meter.
How many homes have smart meters?
At the end of June 2026 there were about 40 million smart meters in Great Britain's homes and small businesses, and smart and advanced meters made up 72% of all meters.
Can my supplier bill me for energy used years ago?
Generally no. Ofgem's back-billing rules stop suppliers charging domestic customers for energy used more than 12 months ago, unless the customer acted obstructively or was billed for it before.