Start with electricity and fuel records
Gather the electricity used in kWh and the fuel consumed in its original units, such as litres of diesel. Use records for the company, sites and year your report covers. If a bill includes another tenant, work out your company’s share before calculating.
You will see two reporting terms in the examples. Scope 1 includes emissions from burning fuel in vehicles or equipment your business owns or controls. Scope 2 covers the generation of energy you buy, such as electricity. These examples calculate those energy emissions; other sources may need separate work.
Multiply the quantity used by an emission factor
An emission factor tells you the emissions associated with one unit of fuel or electricity. For example, a fuel factor can tell you the kilograms of greenhouse gases released for each litre burned. The quantity used is sometimes called “activity data”.
Quantity used × emission factor in kg CO₂e per unit ÷ 1,000 = tonnes CO₂e
CO₂e means carbon dioxide equivalent. It brings the warming effects of different greenhouse gases into a common unit. A factor already expressed in CO₂e should not be multiplied by another warming factor.
Find the factor for the fuel or electricity you are reporting, with the right units, location and year. The factor guide shows where to look and how to check it.
Example 1: 1,000 litres of mineral diesel
Assume a business burns 1,000 litres of 100% mineral diesel in equipment it operates. This example uses the UK DESNZ 2026 full-set combustion factor of 2.66155 kg CO₂e per litre. Use this as a worked UK 2026 calculation. Your own report needs a factor that matches its fuel and reporting period.
Fuel emissions
1,000 litres × 2.66155 kg CO₂e/litre = 2,661.55 kg CO₂e
2,661.55 ÷ 1,000 = 2.66155 tCO₂e, shown as 2.66 tCO₂e in the calculator.
Fuel energy
1,000 litres × 0.009928 MWh/litre = 9.928 MWh, shown as 9.93 MWh.
Because the business operates the equipment, these fuel emissions are Scope 1. Fuel production and transport are outside this combustion factor and are not calculated here. Check the actual fuel specification: a blended fuel can need a different factor.
Factor source: DESNZ 2026 full set, Fuels (mineral diesel) and Fuel properties. The calculator uses net calorific values for fuel energy.
Example 2: 10,000 kWh of purchased electricity
For purchased electricity, the location-based method uses the average emissions of the grid serving your site. Suppose a business buys 10,000 kWh and, for this example only, uses a grid factor of 0.200 kg CO₂e/kWh. This factor is illustrative and has no country or reference year. Do not use it as a default for your report.
Emissions from generating the electricity
10,000 kWh × 0.200 kg CO₂e/kWh ÷ 1,000 = 2.00 tCO₂e
Electricity consumed
10,000 kWh ÷ 1,000 = 10.00 MWh
In a real calculation, replace 0.200 with a documented grid factor appropriate to the location and reporting period. Keep the publication name, factor unit and reference year. A figure in grams per kWh must be divided by 1,000 before entering a calculator field that expects kilograms per kWh.
If this electricity and the diesel above cover the same company and reporting period, the rounded calculator results would be 19.93 MWh of energy, 2.66 tCO₂e of fuel Scope 1 and 2.00 tCO₂e of location-based Scope 2. Those emissions sum to 4.66 tCO₂e for the included activities.
Keep the scopes and methods separate
| Category | In this calculation |
|---|---|
| Scope 1 | Direct combustion from the supported fuels. Refrigerant leakage and process emissions need additional calculations. |
| Location-based Scope 2 | Purchased electricity and district energy, using relevant factors. A renewable contract does not make the location-based figure zero. |
| Market-based Scope 2 | A separate method requiring appropriate contractual and supplier evidence. It is not calculated here or added to location-based Scope 2. |
| Scope 3 | Other value-chain emissions, such as purchased goods, business travel and product use. A full inventory is outside this calculator. |
The GHG Protocol Corporate Standard provides the broader inventory framework. Its Scope 2 guidance explains purchased energy and the two reporting methods. A calculation based only on energy bills should not be labelled a complete business carbon footprint.
For biogenic fuels, keep biogenic CO₂ separate from the scope totals. For natural gas, distinguish gross kWh on a bill from net energy used in the fuel-energy conversion. Enter one gas quantity in one unit to avoid counting it twice.
Keep enough information to repeat the calculation
The factor-selection guide explains how to check the source, unit, geography, reference year and emissions included before using a factor.
- The activity record, quantity and original unit.
- The company, site or vehicle and reporting period it belongs to.
- The factor, its unit, source, geography and reference year.
- Any allocation, estimation or unit conversion.
- The result before rounding and the figure used in the report.
Use the energy and emissions calculator to enter your own quantities and review the results. It keeps your inputs and factor details with the draft when you apply a calculation.
Applying a calculation updates existing energy and emissions answers. Review the fields listed in the calculator before applying, especially if you have already included emissions from other sources.
Put your information into a report.
Answer questions about your company and download a VSME Basic Module report to share with banks and customers. You can start with what you know and return as you gather the remaining information.
Start your reportFree during early access. No account needed.