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Scope 3: what are the calculation methods?


Scope 3 covers indirect emissions linked to the company's activities, but outside its direct boundaries. To calculate these emissions, it is crucial to clearly define the operational boundaries and to use specific emission factors for each category of emissions. Calculation methods include estimating emissions upstream and downstream .
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Scope 3 of the carbon footprint is often the most complex perimeter for organizations to calculate. In this article, you'll learn how to set up effective data collection and the different calculation methods for upstream and downstream emissions.

Calculating Scope 3 Emissions: Basics

Scope 3 encompasses all indirect emissions related to a company's activities, but that occur outside its direct operational boundaries. The complexity of the Scope 3 calculation method results from the diversity of emission sources, but also from the specificities of the calculations related to other organizations that interact with the company concerned.

Before proceeding with the calculation, it is essential to clearly define the operational boundaries, in order to determine precisely what will be included and what will be excluded from the scope of analysis. This does not only ensure data consistency, but also helps avoiding duplication or omission of entries.

For each category of Scope 3 emissions, the use of specific emission factors is essential. These coefficients, typically expressed in kg or tonnes of CO2 equivalent per unit of activity, are used to convert activity data into GHG emissions. These factors are often taken from national or international databases and need to be regularly updated to reflect technological and sectoral developments.

How to calculate Scope 3 emissions?

Upstream Emissions: calculation methods

Purchase of goods and services

To calculate emissions from the purchase of goods and services, organizations can refer to data provided by their suppliers or use industry databases that indicate the average emissions associated with specific goods or services.

Transmission and distribution (off-site)

In order to estimate the emissions related to transport and distribution outside the company's site, it is crucial to consider the type of transport (truck, train, plane, etc.), the distance traveled, as well as the carrying capacity and occupancy rate. Emission factors specific to each mode of transport can be used to obtain an accurate estimate.

Use of sold products

Estimating the carbon footprint of products during their use phase can be complex. This estimate depends on the type of product, its energy efficiency, the frequency of use, and the lifespan of the product.

Business travel, commuting

For business travel, it is essential to collect data on the distance traveled, the mode of transportation, and the frequency of travel. Similarly, for employees' commuting, an internal survey can help determine the means of transportation used, the average distances traveled, and the frequency of travel.

Other upstream indirect emissions

These emissions may cover a variety of activities, with each category requiring a separate calculation method, based on specific emission factors and relevant activity data.

Downstream Emissions: calculation methods

End of life of sold products

Estimating the carbon footprint at the end of a product's life requires taking into account several aspects, such as the number of products recycled, reused, or landfilled. For those that are recycled, the energy and resources required for the recycling process must be estimated. For those that are landfilled, it is important to take into account the emissions generated during their decomposition.

Transmission and distribution (after the point of sale)

The carbon footprint associated with transportation and distribution after the point of sale is influenced by several factors, such as the mode of transportation, the distance traveled, and the frequency of delivery. Sector-specific databases can provide emission factors by type of transport and per kilometer traveled, allowing for accurate estimation.


Emissions associated with investments can come from the activities of the companies in which the organization invests. A common approach is to proportionally assess emissions based on the share of investment in the target firm.

Calculating Scope 3 emissions is a complex but essential process to fully understand an organization's carbon impact.

By combining different methods and using specific software like our carbon footprint calculation software, companies can get a complete picture of their indirect emissions. With a better understanding of their Scope 3 emissions, companies are better positioned to adopt effective emission reduction strategies.

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