Scope 3 emissions are indirect value chain emissions under the GHG Protocol
Formula: Activity Data × Emission Factor = Emissions. Covers purchased goods, business travel, commuting, waste, use of sold products.
What are Scope 3 Emissions?
Scope 3 emissions are indirect greenhouse gas emissions that occur in a company's value chain but are not owned or controlled by the company. The GHG Protocol Corporate Standard defines 15 Scope 3 categories. Scope 3 often represents the largest share of a company's carbon footprint—for many sectors, 70% or more.
Our calculator covers five common categories: purchased goods and services, business travel, employee commuting, waste, and use of sold products. We use simplified emission factors for estimation; for official reporting, use DEFRA, EPA, or industry-specific factors.
Scope 3 Formula
Emissions (kg CO2e) = Activity Data × Emission Factor
Activity data is the quantitative measure (e.g. km travelled, € spent, tonnes of waste). Emission factors convert that into CO2 equivalent. Example: 100,000 km business travel × 0.25 kg CO2e/km = 25,000 kg CO2e = 25 tCO2e.
Example by category
€100,000 purchases × 0.5 kg/€ = 50 tCO2e. 10,000 km commuting × 0.12 kg/km = 1.2 tCO2e. 5 tonnes waste × 0.5 tCO2e/t = 2.5 tCO2e.
Scope 1, 2, and 3
Scope 1: Direct emissions from owned or controlled sources (company vehicles, on-site combustion). Scope 2: Indirect emissions from purchased electricity, heat, steam. Scope 3: All other indirect emissions in the value chain—upstream (supply) and downstream (customers, end-of-life). For compliance emissions costs, use our EU ETS calculator or CBAM calculator.
Emission Factor Sources
Emission factors vary by source. DEFRA (UK) and EPA (US) publish conversion factors. The GHG Protocol provides guidance. Industry databases (e.g. ecoinvent) offer product-specific factors. Our calculator uses simplified averages—replace with official factors for disclosure or science-based targets.
Official resources
Purchased goods & services, business travel, employee commuting, waste, use of sold products. GHG Protocol defines 15 categories in total.
Emissions = Activity × Factor
Often 70%+ of total footprint for many sectors. Critical for net-zero and science-based targets.