Carbon emissions calculator methodology statement

Our calculator allows users to estimate what their business carbon emissions were for a 12-month period each year.

The first year is intended to be retrospective. It should be used as a benchmark for the next years as a business takes carbon-reducing measures and works through its climate action plan.

New businesses without historical data can instead use the benchmark column for their first year of operation.

Intended audience

The calculator has been designed to be as user-friendly as possible. It's primarily geared towards micro, small and medium businesses at an early stage of their climate journey. There is a balance between user experience and accuracy to allow a wide range of businesses to get an estimate of specific areas of their footprint in a straightforward way.

Testing and research

User testing and human research showed that businesses needed:

• a simple-to-use calculator to get started
• to learn to become accurate over a three-year period with the goal of getting started in mind

Purpose

The main intentions of the calculator are to:

• embed good practices
• provide users with a snapshot of their emissions over a four-year period (one benchmark year, plus three consecutive years)
• estimate emissions and develop accuracy over time through knowledge and good practice
• allow for carbon calculation to become more accessible to early-stage businesses

Workbook goals

By using the workbook, the intention is for businesses to:

• attempt a start with measuring their supply and value chain
• consider becoming more accurate independently of this calculator after three years
• gain the confidence to move onto a more advanced calculating tool
• start to understand and think of their emissions in relation to scopes one, two, and three on initiation and delivery of their actions over the years

Energy

To calculate energy, we use data from the UK government's:

• Department for Energy Security and Net Zero
• Department for Business, Energy & Industrial Strategy

This gives a breakdown for how much CO2e* is emitted for each source of energy. Where applicable, we use gross calorific value conversion factors which is the basis of most energy bills.

*We display the results of our carbon calculator in CO2e which stands for carbon dioxide equivalent. CO2 only measures carbon dioxide. CO2e, however, measures CO2 as well as other greenhouse gases such as methane and nitrous oxide.

Waste

Waste conversion factors for the categories "landfill", "recycling", and "food waste" come from the conversion factors on gov.uk.