guide · last reviewed 2026-07-13
Scope 1, 2, and 3 for small suppliers
Plain-English context for emissions questions that appear in supplier questionnaires.
Summary
Emissions questions can be useful but easy to overstate. Mark estimates and review assumptions before sharing.
Audience: Small suppliers receiving carbon questions. Risk level: medium.
Start with what you know
In plain terms: Scope 1 covers fuel your business burns directly (vehicles, heating, machinery), Scope 2 covers the electricity you buy, and Scope 3 covers emissions in your wider chain (purchased goods, freight, travel, and similar). For most small suppliers the practical starting inputs are energy bills, fuel receipts or mileage records, and basic site information — these usually support a first answer on Scopes 1 and 2 without new measurement systems.
Be clear about estimates
Most small-supplier emissions figures are estimates, and buyers know this. State the basis — which months, which sites, which conversion factors — and mark anything extrapolated or partial as such. Presenting an estimated figure as assured or complete is the single most damaging mistake in a carbon answer, because it converts a data gap into a credibility problem.
Connect to the request
Buyers usually ask emissions questions in a specific shape: a number for a period, a yes/no on whether you measure, or a description of your approach. Answer the question as asked before adding context, then note limitations briefly. Scope 3 in particular is hard for small businesses — saying you do not yet measure it, and what you would need in order to start, is a respectable answer.
Source basis
Regulatory or legal conclusions should be reviewed against current official sources before being used externally.
Keep reading
Related resources
More practical material from the resource library.
How to answer a customer ESG questionnaire
A practical guide for small suppliers responding to customer sustainability and ESG requests.
Supplier sustainability questionnaire guide
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CSRD supplier requests, explained for SMEs
Understand why larger customers may ask smaller suppliers for sustainability information.