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.
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Gas Bill Calculator
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 refers to the amount of gas you consume, measured in kilowatt-hours (kWh). However, gas meters typically measure consumption in cubic meters (m³) or cubic feet (ft³). To calculate how many units of gas you’ve used (in kWh), your energy supplier converts the volume of gas recorded on your meter into kilowatt-hours using a standard formula.
The calculation factors in:
- Volume of gas used (m³ or ft³)
- Calorific value (the energy content of the gas)
- Correction factor (to adjust for pressure and temperature differences)
The total units of gas consumed in kilowatt-hours (kWh) are used to calculate your gas bill based on the unit rate your supplier charges.
Example:
If you use 100 cubic meters (m³) of gas, it could convert to around 1,110 kWh of gas units, depending on the specific conversion factors used by your energy supplier.
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 renewable 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 | 1250 | 15,000 |
| 5 Bedroom House | 47 | 1417 | 17,000 |
We also have an electricity bill calculator and an energy bill calculator available (to calculate a combined gas and electricity bill).
