How to choose emission factors.

Start with the type of energy

Electricity bought from the grid

For the location-based emissions figure in this tool, you need an average factor for the electricity grid serving your site. “Location-based” means the calculation reflects where you use electricity. Look for a published grid factor from the relevant authority or grid operator, with a stated year and method.

For a site outside the UK, find a factor for its own grid and reporting period. If you need help locating one, ask the authority, grid operator or an adviser: “Which published grid-average factor should we use for electricity consumed at [location] in [year], for location-based Scope 2 reporting? Please include the unit and source.”

A supplier’s green-tariff or residual-mix figure may describe a different method. The GHG Protocol Scope 2 Guidance, chapter 6, explains which sources fit each method.

Fuel used in vehicles, equipment or heating

Look up the fuel you actually bought in a published factor dataset for company reporting. Check the specification on the invoice: pure mineral diesel and a blended road fuel can need different figures. The calculator includes UK 2026 fuel reference factors for you to review.

Purchased heat, steam or cooling

Ask the supplier for a factor for the heat or other energy it supplied to your site, with the year, unit and calculation method. Use that alongside the quantity on your bill.

Check five things before using the number

A factor might be written as “kg CO₂e per litre”. That means kilograms of carbon dioxide equivalent for each litre of fuel. CO₂e puts the warming effects of the greenhouse gases included in the calculation into a common unit.

• Energy type. Does it describe your fuel, electricity grid or heat supply?
• Place. Is it relevant to the site or supply you are reporting?
• Year. Which reporting period is the factor intended for? The publication date alone may not answer this.
• Unit. Does the factor use the same quantity unit as your record, such as litres or kWh?
• Emissions included. Does it cover burning the fuel or generating the electricity, or also earlier activities such as producing and transporting fuel? Does it include CO₂ alone or other greenhouse gases?

If you cannot establish the match, keep the calculation open while you find the missing information. The calculator lets you enter a factor and its source; it does not choose the correct source for your company.

Check the units with a simple example

If the source gives 200 grams per kWh, divide by 1,000 to enter 0.200 kilograms per kWh. If your energy is in MWh, remember that 1 MWh equals 1,000 kWh. Convert the units before multiplying.

The calculation guide also walks through fuel emissions and energy use.

Keep a note you can understand next year

Save the publisher, dataset and worksheet, factor value and unit, reporting year and applicable location. Keep the link or document alongside the bill and calculation.

For an electricity factor from the worked source-finding example, a useful note would identify “UK government conversion factors 2026, full set, UK electricity, Electricity generated, kg CO₂e per kWh”, followed by the exact value used and the site it applies to.

When you apply calculator results, the factor details you entered are saved with the draft. Keep the original publications in your own records too. If the factor changes next year, you can distinguish that change from a change in how much energy you used.

Questions that often come up

We buy renewable electricity. Should the factor be zero?

The location-based calculation still uses the grid average. Contract-specific claims belong to the separate market-based method, which requires appropriate supporting information. This calculator produces the location-based result.

My gas bill shows both kWh and cubic metres. Which do I enter?

Choose one quantity and its matching unit. Entering both would count the same gas twice. For fuel energy conversions, also check whether the bill and factor use gross or net calorific values, two different ways of measuring the energy in a fuel.

Can I use a factor that includes the whole fuel lifecycle?

For fuel burned by the business, the direct-emissions calculation needs the combustion part. Production and transport of fuel belong to other emissions categories. Use the scope explanation to keep those categories separate.