Gas Bill Calculator
We've created this gas bill calculator to help you estimate how much you should be expecting to pay for your gas bill over any set period of time.
This may be because you are moving home and want to work out how much more or less you may have to pay, or maybe you are looking to switch tariffs and see how much you could save on your utility bills.
Whatever your reason, keep reading to see how to use our free energy bill calculator and find out what you need to know.
Use our referral link, and we'll both get £50 credit once your switch is complete.
Existing customer? Find out how you can benefit too. T&Cs apply (only one switching offer per household)
How to use our gas bill calculator
You need to start by deciding how many days you want to look at, one day, one week, one year or anything in between.
Next, the energy cost calculator needs to know your daily gas consumption. This can be worked out from your latest energy bill, or you can use our average estimates below.
The next two pieces of information you will need to get from your utility bill will differ depending on your energy supplier and tariff.
Your unit rate is how much you pay for each unit of gas, and your standing charge is a fixed amount you pay per day regardless of how much energy is used.
Once you put all these details in, you will automatically see a breakdown of your total unit charge over the period you set, the total cost of your standing charge, and your overall bill for that period of time.
What is a Unit of Gas?
A unit of gas is one kilowatt-hour (kWh), which is what your bill is priced in. Your meter, though, records volume — cubic metres (m³) on a metric meter or cubic feet (ft³) on an older imperial one — and your supplier converts that volume to kWh using a standard formula that accounts for the calorific value of the gas and a correction for pressure and temperature.
If your bill or your meter gives you volume rather than kilowatt hours, the gas meter reading calculator does that conversion on the same formula your supplier applies, in both metric and imperial. Bring the kWh figure back here to cost it.
What is a Daily Standing Charge?
A daily standing charge is a fixed cost that you pay every day to your energy supplier, regardless of how much gas you use. It covers the costs associated with maintaining the gas network, including:
- Maintaining energy infrastructure (like power lines and substations)
- Billing and customer services
- Government schemes for zero-carbon energy
The daily standing charge is applied as a set rate per day and is added to your gas bill alongside the unit rate charges for the gas you use. Even if you don't use any gas, you'll still need to pay the daily standing charge.
Average gas usage per household type (2025)
If you aren't sure of your gas usage, below we have given you the average monthly usage for various property types in the UK according to Ofgem.
Your usage will vary depending on property age, number of occupants, types of appliances etc.
| Property Type | Average Daily Unit Usage | Average Monthly Unit Usage | Average Annual Unit Usage |
|---|---|---|---|
| 1 Bedroom Flat | 21 | 625 | 7,500 |
| 2 Bedroom House | 25 | 750 | 9,000 |
| 3 Bedroom House | 32 | 958 | 11,500 |
| 4 Bedroom House | 41 | 1,250 | 15,000 |
| 5 Bedroom House | 47 | 1,417 | 17,000 |
Note: This is the average monthly usage over 12 months. Usage may be higher in the winter months.
We also have an electricity bill calculator and an energy bill calculator available (to calculate a combined gas and electricity bill).
Frequently asked questions
What is a unit of gas?
A unit of gas refers to the amount of gas you consume, measured in kilowatt-hours (kWh). Gas meters typically measure consumption in cubic meters or cubic feet, which your supplier converts to kWh using a standard formula factoring in volume, calorific value and a correction factor.
What is a daily standing charge?
A daily standing charge is a fixed cost that you pay every day to your energy supplier, regardless of how much gas you use. It covers costs like maintaining energy infrastructure, billing and government schemes for zero-carbon energy.
How much gas does a typical UK household use?
Ofgem’s typical household figure is 9,500 kWh of gas a year, or about 26 kWh a day, since 1 July 2026. It was 11,500 kWh before that — a 17% reduction that reflects Ofgem revising the assumption, not households suddenly using less, so a bill quoted on the older figure is not comparable. Ofgem publishes low, medium and high values rather than a figure per bedroom; the per-bedroom estimates in the table above are a separate industry rule of thumb. Usage is far higher in winter than the annual average implies.
Other calculators
- £Calculator
Electricity Bill Calculator
Calculate your electricity bill over any time period using your standing charge, unit rate and daily usage.
Open calculator → - £Calculator
Energy Bill Calculator
Calculate your gas and electricity bill over any time period using your standing charge, unit rate and usage.
Open calculator → - £Calculator
Standing Charge Calculator
Work out how much your daily standing charge is costing you per week, month and year for gas and electricity.
Open calculator →
Written by
Rob Gibbs
Hi, I'm Rob, and I run Energy-Review.co.uk. I initially started this project in 2018 when I was looking to switch energy suppliers and found there wasn't a website that provided simple, data-backed reviews on all the suppliers available. Since then, I have spent a lot of time (too much, some may say!) looking at all publicly available data about each supplier and writing reviews using this information. These reviews are updated as regularly as possible, and any data is backed up by a source where necessary. I have also started writing guides on various energy-related topics, which hopefully you will find useful. If you find any issues, please use our contact form to let us know.