The 15 Scope 3 Categories Explained

Scope 3 emissions cover everything that happens in your value chain: upstream suppliers and downstream customers. For most companies, Scope 3 represents the vast majority of their total carbon footprint. Here is what each category covers and why it matters.

Where most of your footprint lives

For services-oriented companies, investment firms, and multi-entity groups, Category 1 (Purchased Goods & Services) is where the bulk of emissions concentrate. Most of what your company buys gets counted here: from office supplies and IT equipment to consulting fees and raw materials.

This is also the category where measurement method matters most. A spend-based approach assigns the same emission factor to every dollar spent in a category. An activity-based approach identifies the actual product and matches it to specific lifecycle data.

Spend-based vs activity-based: why the method matters

The GHG Protocol allows multiple calculation approaches for Scope 3. The choice of method directly affects the quality and usefulness of your data.

What CSRD expects from your Scope 3 data

Under CSRD and ESRS E1, companies must report Scope 3 emissions that can withstand external assurance. The current requirement is limited assurance, but even that demands traceable, documented calculations, something spend-based estimates struggle to survive.

In practice, this means:

• A traceable path from invoice → what was bought → reported emission
• Documented emission factors with source, method, and quality rating
• Consistent scope boundaries and category definitions year over year

Spend-based estimates end at a category-level average with no connection to actual purchases. Under these requirements, that is increasingly difficult to defend. The direction of regulation is clear: more granularity, more traceability, more accountability.