Measuring your company’s carbon footprint is the essential first step in any sustainability or CSRD compliance program. Without a baseline measurement, you can’t set meaningful targets, track progress, or make credible disclosures to investors and customers.

This guide explains how to measure your company’s carbon footprint, what methodology to use, and how to build a process that can be repeated annually.

What is a corporate carbon footprint?

A corporate carbon footprint is the total greenhouse gas (GHG) emissions associated with a company’s operations and value chain, expressed in tonnes of CO2 equivalent (CO2e). It covers three categories of emissions, known as scopes:

• Scope 1: Direct emissions from sources owned or controlled by the company (combustion, process emissions, company vehicles)
• Scope 2: Indirect emissions from purchased electricity, heat, and steam
• Scope 3: All other indirect emissions in the value chain, including purchased goods, business travel, employee commuting, and the use of sold products

For most mid-market companies, Scope 3 is the largest category, often exceeding 70% of total emissions.

Step 1: Choose your methodology

The globally accepted framework for corporate GHG measurement is the GHG Protocol, which covers both the Corporate Standard (Scope 1 and 2) and the Corporate Value Chain Standard (Scope 3). Both the EU’s ESRS and ISSB standards reference GHG Protocol methodology.

For a first measurement, a hybrid approach works well: spend-based calculations for most Scope 3 categories (using financial data you already have) combined with activity-based data for Scope 1 and 2 (energy and fuel invoices).

Step 2: Set your organizational boundary

Decide which legal entities and operations to include. The two GHG Protocol approaches are:

• Equity share: Include emissions proportional to your equity ownership in each entity
• Operational control: Include emissions from operations over which you have operational control

Operational control is more common for CSRD purposes. Document your boundary clearly — it affects comparability year-over-year.

Step 3: Collect activity data

For Scope 1 and 2, collect data from energy invoices, fuel purchase records, and fleet management systems. For Scope 3, start with your accounting system — spend data by supplier category provides the foundation for spend-based calculations.

Step 4: Apply emission factors

Multiply activity data by the relevant emission factors to convert physical or financial data into tonnes of CO2e. Use authoritative sources: IEA for grid emission factors, DEFRA for UK factors, Exiobase or USEEIO for spend-based Scope 3 factors.

Step 5: Calculate and document results

Sum your emissions across all scopes and categories. Document your methodology, data sources, emission factors, and any material assumptions or limitations. This documentation is essential for CSRD assurance and for enabling year-on-year comparability.

Step 6: Review and improve

A first measurement will have gaps and approximations. Use the results to identify where data quality can be improved — particularly for your highest-emission categories. Build a plan to move from spend-based to activity-based data for the most material Scope 3 categories.

How Coolset supports carbon footprint measurement

Coolset’s carbon accounting platform automates the measurement process, supporting spend-based, activity-based, and supplier-specific calculations aligned with the GHG Protocol. The methodology is certified by TÜV Rheinland. The platform identifies emission hotspots, supports supplier data requests, and maintains the audit trail needed for CSRD limited assurance. Book a demo to see how it works.