A carbon footprint is measured in tonnes of carbon dioxide equivalent (tCO2e). The carbon dioxide equivalent (CO2e) allows the different greenhouse gases to be compared on a like-for-like basis relative to one unit of CO2. CO2e is calculated by multiplying the emissions of each of the six greenhouse gases by its 100 year global warming potential (GWP).
A carbon footprint considers all six of the Kyoto Protocol greenhouse gases: Carbon dioxide (CO2), Methane (CH4), Nitrous oxide (N2O), Hydrofluorocarbons (HFCs), Perfluorocarbons (PFCs) and Sulphur hexafluoride (SF6).
Types of carbon footprinting
The main types of carbon footprint for organisations are:
Emissions from all the activities across an organisation, including buildings' energy use, industrial processes and company vehicles.
Includes emissions which are outside an organisation's own operations (also known as Scope 3 emissions). This represents emissions from both suppliers and consumers, including all use and end of life emissions.
Emissions over the whole life of a product or service, from the extraction of raw materials and manufacturing right through to its use and final reuse, recycling or disposal.
Carbon footprinting guide
Our 20-page guide to carbon footprinting explains what is included in organisational and product footprints, how you can measure and communicate them, and the benefits of doing so. We also set out the specific steps you need to take to calculate your carbon footprint(s), and some of the key things to consider if you do.
- Introduction to carbon footprinting
- Organisational carbon footprints
- Why calculate your organisational carbon footprint?
- How to calculate an organisational carbon footprint
- Communicating your organisational carbon footprint
- Product carbon footprint
- Why calculate your product carbon footprint?
- How to assess your product carbon footprint
- Communicating your product carbon footprint
Publication date: March 2012; Publication code: CTV043 v2
Download the Carbon Trust Carbon Footprinting guide:
Greenhouse gas conversion factors are used to calculate the amount of greenhouse gas emissions caused by energy use. Our conversion factors guide contains these factors along with a spreadsheet to enter your usage and calculate carbon emissions.
For further support, find out more about our carbon footprinting services: