Help Using Gas Bill Calculator

We've tried to make the Gas Bill Calculator as user friendly as possible with minimal user input whilst still being capable of giving a fairly accurate estimation of your bills.

There are however many different types of gas supplier tariff and there have been many examples of users that have more advanced needs when calculating their gas bills, so we have included advanced settings in our calculator.

This help section aims to provide detailed information on the advanced settings as well as potential configuations to help calculate the different types of tariffs out there.

Many of the below figures won't need to be changed but if you feel they do, you'll find most of them on your bill/s.

New Gas Bill Calculator

The new Gas Bill Calculator has been designed to make calculating bills simpler.

A 3 step process means you don't always have to know the exact figures for your tariff as the new drop down boxes can auto-fill these in for you.

Step 1 (Optional)

Choose how you pay for your gas. The item you select here influences the figures filled in step 3.

If you're not sure of your tariff costs but know your tariff, you can choose it from the 'Supplier' and 'Tarrifs' drop down menu. This will automatically fill in the 'Standing Charge' and 'Price Per KWh' amounts.

Gas Supplier and Tariff

Step 2

Choose your 'Meter Type' and enter your meter readings in the next boxes.

If you're not sure what type of meter you have take a look at our Gas Meters page.

Gas Meter Readings

Step 3

Finally, if required you can click the 'Tweak Conversion Factors' link if you have an imperial gas meter and need to fine tune the conversion figures.

Otherwise, click 'Calculate' to be taken to the 'Your Bill' page and see detailed information about your bill.

Gas Calculation


Your usage threshold is the amount of energy, in Kwh you will pay the tier 1 rate for.

Not all gas suppliers offer energy thresholds so it may be necassary to edit this value if you know you don't have a tiered or staged tariff.

If you pay a single rate for your gas set the threshold to 0 then set the tier 1 rate to zero. Ensure you update your Tier 2 Gas Rate to accurately reflect your price in pence per unit.

Tier 1 Rate

Your Tier 1 Gas Rate is the top price you pay for each unit, this is normally around 8 pence but varies depending on both your supplier and your tariff.

When not on a tiered gas plan, set this and the threshold to 0 and update your unit rate in the Tier 2 Rate box.

Tier 2 Rate

The Tier 2 Gas Rate is the lower price you pay for your energy once you have reached the quarterly threshold set in the threshold box (as a yearly amount).

If you don't have a tiered plan, set threshold and tier 1 rates to 0 then just enter your price per unit in this box.

Conversion Factor

The conversion factor is a value used to convert meter units into energy (Kwh).

This value will always be visible on your bill.

Calorific Value

The calorific value represents the amount of energy given off when a mass of fuel if burned.

It can be dependant on several factors including temperature, pressure, the gas itself and more.

This value can also always be found on your bill.

Volume Correction

Volume Correction or, 'Correction Factor' takes into account changes in the volume of gas depending on temperature and pressure.