How Is Corporate Carbon Emission Calculated? Scope 1, 2, 3 Guide

Calculating a business's carbon emissions is a far more structured process than an individual calculation, and it relies on a single internationally recognized standard: the GHG Protocol (Greenhouse Gas Protocol). In this guide, we explain the Scope 1, 2, and 3 distinction that forms the basis of corporate emissions calculation, the inventory-building process, and the most common mistakes.

What Is the GHG Protocol, and Why Is It the Global Standard?

The GHG Protocol is an accounting standard developed by the World Resources Institute (WRI) and the World Business Council for Sustainable Development (WBCSD) that allows companies worldwide to measure their greenhouse gas emissions consistently and comparably. Nearly all major sustainability reporting frameworks — CDP, SBTi, CSRD — adopt the GHG Protocol as their underlying methodology, which is why a "correct" corporate carbon calculation must be based on the GHG Protocol's Scope distinction.

Scope 1 — Direct Emissions

Scope 1 covers emissions from sources the business DIRECTLY owns or controls:

• Stationary combustion: Natural gas, coal, LPG, or fuel oil burned in factory boilers, generators, or heating systems.
• Mobile combustion: Fuel consumption of the company's own vehicle fleet (trucks, forklifts, passenger vehicles).
• Fugitive emissions: Refrigerant gas leaks from air conditioning/cooling systems — since some gases (e.g. SF6) have a global warming potential thousands of times that of CO2, even a small leak can have a major emission impact.

Scope 2 — Purchased Energy

Scope 2 covers the indirect emissions arising from the GENERATION of the electricity, steam, heating, or cooling energy the business purchases. There are two calculation methods:

• Location-based: Uses the average grid electricity emission factor of the country/region where the facility is located (e.g. 0.442 kg CO2e/kWh for Turkey).
• Market-based: Takes into account the actual source of the electricity the business purchases (e.g. renewable energy certified purchases) — for a business with green energy certificates, this value can be close to zero.

Grid electricity intensity varies greatly from country to country: it's 0.056 kg CO2e/kWh in France, which has a high share of nuclear energy, versus up to 0.653 kg CO2e/kWh in coal-heavy Poland — more than an 11-fold difference. You can find all country coefficients on our Bibliography page.

Scope 3 — Value Chain

Scope 3 covers the INDIRECT emissions across a business's value chain (suppliers, customers, employees) and, under the GHG Protocol Scope 3 Technical Guidance, is divided into 15 sub-categories — from purchased goods and services to business travel, from the use of sold products to investments. For most companies, Scope 3 can account for 70-90% of TOTAL emissions — which means a calculation focused only on Scope 1-2 sees only a small fraction of the real carbon footprint. You can find the full list of all 15 categories and which method (spend-based vs. unit-based) each uses in detail in the Scope 3 section of our Bibliography page.

Steps to Build an Emissions Inventory

1. Define organizational and operational boundaries: Which facilities, which activities will be included in the inventory?

2. Data collection: Fuel bills, electricity bills, fleet mileage records, business travel records, and supplier spend data are collected.

3. Apply coefficients: Each data item is converted to kg CO2e by applying the relevant emission coefficient.

4. Verification and reporting: Results are reviewed, third-party assurance is obtained if necessary, and the results are compiled into a report compliant with a standard such as ISO 14064.

Common Mistakes

Mixing up Scope 1-2-3: For example, mistakenly recording the fuel consumption of the company's own fleet (Scope 1) under Scope 3 undermines the comparability of the report.

Incorrectly including biogenic CO2: CO2 released from burning non-fossil (plant/wood-derived) biomass is NOT INCLUDED in Scope totals under the GHG Protocol — because it is considered a net-zero cycle. We cover this topic in more detail in the Biogenic Carbon section of our Bibliography page.

Reporting only Scope 1-2: Skipping Scope 3 usually means ignoring the vast majority of total emissions, and an increasing number of regulatory frameworks (like CSRD) are now mandating Scope 3 reporting as well.

Worked Corporate Example

Monthly Scope 1-2 calculation for a manufacturing facility:

Scope 1 (natural gas boiler, 5,000 m³/month): 5,000 × 2.02 kg CO2e/m³ = 10,100 kg CO2e
Scope 2 (electricity, 20,000 kWh/month, Turkish grid): 20,000 × 0.442 kg CO2e/kWh = 8,840 kg CO2e
Total Scope 1+2 ≈ 18,940 kg CO2e/month (excluding Scope 3 — this figure typically multiplies several times over once the supply chain and other indirect sources are added)