How to collect Scope 3 data from suppliers
How to decide which suppliers to ask, what to ask for, how to keep requests proportionate, and how to turn the answers into usable Scope 3 numbers.
Scope 3 emissions usually make up most of a company's footprint, and most of the data sits with suppliers. Collecting it badly wastes your time and theirs. This guide covers a proportionate approach. For the basics, read Scope 1, 2 and 3 explained.
Step 1: Find out where your emissions are
Do not email every supplier. First estimate Scope 3 with spend-based factors, which multiply what you spend in a category by an average emission factor. The Greenhouse Gas Protocol defines 15 Scope 3 categories. For most manufacturers and retailers, purchased goods and services dominate. This rough estimate shows which categories and suppliers matter.
Step 2: Prioritise suppliers
Sort suppliers by spend and by estimated emissions. A common approach is to engage the suppliers that cover the majority of your spend or emissions, then use estimates for the rest. Say in your methodology what share you covered.
Step 3: Keep requests proportionate
Under the Omnibus changes, a company that reports under the CSRD cannot require suppliers and other value-chain companies with an average of up to 1,000 employees to provide sustainability information beyond the essential datapoints in Annex II of the voluntary standard (Delegated Regulation (EU) 2026/1560). Those smaller companies may decline anything further. The cap applies from financial years beginning on or after 1 January 2027 and covers information gathered for CSRD reporting; it does not stop requests made for other legal reasons. Ask your adviser how it applies to your suppliers, and base your request on the Annex II datapoints rather than a long bespoke questionnaire.
Step 4: Decide what to ask
Keep the first request short. A useful starting set:
- Supplier's Scope 1 and Scope 2 emissions for the last year, and the method used.
- Whether the figures were checked by a third party.
- Product- or customer-specific emissions, if available.
- The reporting boundary and year.
- A contact for follow-up.
Our supplier data request template gives you this as a spreadsheet.
Step 5: Send, chase and record
Send one clear message with a deadline, an example of a completed form and a named contact. Chase once after a week or two. Keep a log of who responded, when, and in what format.
Step 6: Validate what comes back
Check units, years and boundaries. Compare against your spend-based estimate. If a supplier reports a figure ten times lower than the estimate, ask why before you use it.
Step 7: Use a data quality ladder
Not all data is equal. Use the best available for each supplier and label it:
- Supplier-specific, verified.
- Supplier-specific, unverified.
- Activity-based estimate (for example, tonnes of material times a factor).
- Spend-based estimate.
Plan to move your biggest suppliers up the ladder over time.
Step 8: Document and improve
Record the factors, sources, years and assumptions. Auditors will ask. Review each year, and replace estimates with supplier data where you can.
Software and services
StepChange
Climate and ESG software platform covering Scope 1-3 and portfolio emissions, vendor ESG management and climate and nature risk.
Assent
Supply chain sustainability and product compliance management.
TraceX Technologies
Traceability platform for EUDR compliance, with risk assessment and due diligence workflows for agricultural supply chains.
Achilles
Supply chain risk management, supplier audits and carbon programmes for buyers and suppliers, with an ESG-based sustainability score.
Ordered by verified reviews and relevance. Listings are never ranked by payment. See all 66 providers
IsoMetrix
Software suite combining ESG, risk and compliance, and health and safety modules for industrial and financial companies.
One Click LCA
LCA and EPD software for construction and manufacturing, covering buildings, infrastructure and product carbon footprints.
Normative
Carbon accounting platform for calculating, reporting and reducing Scope 1, 2 and 3 emissions, now merging with Greenly.
Benchmark Gensuite
EHS and ESG software suite with reporting tools including BRSR and BRSR Core.
Ordered by verified reviews and relevance. Listings are never ranked by payment. See all 146 providers
See also how to choose carbon accounting software.
Official sources
This guide is general information, not legal, tax or investment advice. Rules change; check the official sources and talk to an adviser before you rely on it.
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