How to calculate your company’s carbon footprint

Still in the dark about your carbon footprint? Charlotte High of Global Action Plan reveals all

One in four UK firms now measures its carbon footprint, according to a study by Siemens Financial Services. Is it time you did too? If so, how?

There are different types of carbon emissions, classified by the degree of control you have over them. In most cases, the closer you are to the source the easier they are to measure.

Direct emissions are fully the responsibility of the business, such as fuels burnt on site or emissions from company vehicles. Different types of fuel release varying amounts of CO 2 as they burn (the government’s environment department DEFRA has published information on these at Look at accounts, invoices and tank sizes to find out how much of each type you are using, and multiply by the appropriate conversion factor.

For the sake of accuracy, you ideally want to know how much fuel you use over a year. If this is not possible, take what information you have and extrapolate it over 12 months.

If you don’t keep fuel consumption records, you can calculate them from vehicle mileage and fuel consumption, or by keeping a journey log and determining the number of road miles driven using an online tool such as AA Route Finder.

Air travel emissions can be calculated using an online international distance finder ( and the DEFRA figures.

Emissions from electricity and gas usage are technically controlled by the power station, but are influenced by how much your business uses on site through the use of equipment, lighting, heating and cooling.

Again, DEFRA has published figures on the average amount of CO 2 released per kilowatt hour (kWh) of mains-fed electricity and gas in the UK. To calculate your usage, find out the amount of kWh you use in a year. If you have a meter, your bills will show this figure. If not you can estimate your use by finding out the wattages of all mains power using equipment, and multiplying this by the approximate number of hours they are switched on for. Indirect emissions arise from the products and services associated with your business, but not controlled directly by you, such as those arising from the preparation of materials that are used by your business as part of creating your product or service. Other examples include emissions from: vehicles used by suppliers; customers or contractors visiting your site; waste disposal and the use, transportation and disposal of your product or service.

In fact, the number of indirect carbon emissions arising from your business can be almost limitless, so to partially resolve this simply be open about exactly what you’re including and ensure those methods are consistent year on year.

There is currently no legal or even widely accepted content for a carbon footprint, making comparisons inequitable. However, the main reason for calculating your carbon footprint is to reduce it. So make sure you’re honest and consistent, using publicised conversion statistics wherever possible, and setting challenging, but achievable reduction targets.

Happy measuring!

Global Action Plan is a charity that provides free environmental support and advice to small and mid-sized businesses in London. For information visit: It is one of the many members of the London Environmental Support Service (LESS), a one-stop-shop for businesses to access a network of environmental support providers in London. LESS is made up of over 30 such suppliers from the public and private sectors, and much of the support available is free. For information visit:


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