Free tool · Scope 3
Free Scope 3 emissions calculator
Estimate your Scope 3 value-chain emissions in seconds with a spend-based screening model. Enter your annual spend across four key categories and get an indicative tCO2e figure live. Scope 3 is typically 70–90% of a company's total footprint, so it is where most of your impact — and your reporting risk — lives.
Your annual spend
Enter approximate annual spend in EUR for each category. Leave a field at 0 if it does not apply.
Indicative result
Updates live as you type.
Estimated Scope 3 emissions
0 tCO2e
≈ enter your spend to see an estimate
Screening estimate only. Spend-based factors are coarse averages — supplier-specific data is far more accurate (see the disclaimer below).
This is an indicative estimate, not a GHG inventory
This calculator multiplies your spend by standard average spend-based emission factors (in kgCO2e per EUR): purchased goods & services 0.45, capital goods 0.40, business travel 0.55, and upstream freight & logistics 0.60. These are coarse industry averages used for screening — they are not a substitute for a full GHG-Protocol Scope 3 inventory or professional advice.
Real emission factors vary significantly by country, year, sector and energy source, and spend-based methods carry high uncertainty. Treat the result as a rough order-of-magnitude indication only. For decision-grade figures, CarbonTool uses precise, source-, country- and year-specific emission factors with a full audit trail.
Spend-based screening vs supplier-specific data
A spend-based estimate is the fastest way to size your value-chain footprint and find the biggest categories to prioritise. But because it assumes every euro of spend in a category emits the same, it cannot reflect which suppliers are actually decarbonising. To report credibly and to track real reductions, you move from spend-based screening to supplier-specific data.
Spend-based (this tool)
Fast, low-effort screening from financial data. High uncertainty, blind to supplier-level differences, and improvements by suppliers never show up in your numbers.
Supplier-specific (CarbonTool)
Primary data collected from your suppliers via CarbonTool's supplier portal. Far more accurate, audit-ready, and it captures the reductions your suppliers actually make.
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A Scope 3 calculator estimates the greenhouse gas emissions in your value chain — the indirect emissions outside Scope 1 (direct) and Scope 2 (purchased energy), such as purchased goods and services, capital goods, business travel, and upstream freight. This free tool uses a spend-based method: it multiplies your annual spend in each category by an average emission factor (kgCO2e per EUR) to produce an indicative total in tonnes of CO2e (tCO2e). It is a screening estimate, not a full GHG-Protocol inventory.
Spend-based estimation multiplies financial spend by an average emission factor, so every euro spent in a category is assumed to emit the same. It is fast and useful for screening, but it has high uncertainty and cannot reflect how individual suppliers actually perform. Supplier-specific data uses primary figures collected directly from your suppliers — it is far more accurate, audit-ready, and it captures the real reductions your suppliers make over time. CarbonTool collects supplier-specific data through its supplier portal.
No — treat it as a rough order-of-magnitude screening figure only. The calculator applies coarse average factors (purchased goods 0.45, capital goods 0.40, business travel 0.55, freight & logistics 0.60 kgCO2e per EUR) that do not reflect your specific country, year, sector or energy mix. Spend-based methods carry high uncertainty. It is not a substitute for a full GHG-Protocol Scope 3 inventory or professional advice. For decision-grade numbers, build a proper inventory with precise, source-specific emission factors.
For most companies, Scope 3 represents roughly 70–90% of the total carbon footprint, because it covers the entire upstream and downstream value chain. That means the majority of your emissions — and your reporting obligations under frameworks like CSRD — sit in Scope 3. Screening with a spend-based estimate helps you find the biggest categories quickly, then prioritise where to collect better data.
You move from a spend-based screening estimate to primary data collected directly from your suppliers. CarbonTool provides a dedicated supplier portal that lets you request, gather and validate supplier-specific emissions data with PCAF-style data-quality scoring — turning a rough estimate into an audit-ready figure. See CarbonTool's supply chain platform at /platform/supply-chain to learn how it works.
Turn this estimate into a real inventory.
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