The 15 Scope 3 Categories Explained for UK SMEs

When a customer asks for your "Scope 3 data," the request can mean very different things depending on which of the fifteen Scope 3 categories they care about. Most UK SMEs do not need to measure all fifteen. But knowing what each category covers — and which ones your business actually generates — is the difference between a confident, defensible answer and a guess.

This guide walks through all fifteen categories as defined by the Greenhouse Gas Protocol, in plain English, with a focus on what they mean for a small or mid-sized UK supplier. If you have already read our guide on Scope 1 and 2 emissions, this is the natural next step.

What "Scope 3" actually covers

The Greenhouse Gas Protocol Corporate Value Chain (Scope 3) Standard — published in 2011 and the international reference that almost every reporting framework rests on — defines Scope 3 as all indirect emissions in a company's value chain that are not already counted as Scope 1 (direct) or Scope 2 (purchased energy).

The standard divides Scope 3 into fifteen categories: eight upstream (categories 1 to 8, covering everything that feeds into your business) and seven downstream (categories 9 to 15, covering what happens after you sell). The split matters because most SMEs generate meaningful emissions in only a handful of these.

A point that trips people up: your Scope 1 and 2 emissions are your customer's Scope 3 Category 1. When a large company buys from you, the emissions you produce making their goods become part of their "purchased goods and services" footprint. That is why the requests land on your desk — not because you have to report Scope 3 yourself, but because you are an input to someone else's Scope 3 calculation.

The eight upstream categories (1–8)

Upstream emissions cover everything leading up to the point you sell your product or service.

Category 1: Purchased goods and services

Emissions from producing the goods and services your company buys — raw materials, components, packaging, professional services. For most product businesses, this is the single largest Scope 3 category. It is also the category your own customers are asking you about, because your output is their Category 1 input.

Category 2: Capital goods

Emissions from producing the long-lived assets you purchase — machinery, vehicles, buildings, IT equipment. The distinction from Category 1 is durability: capital goods are assets you depreciate, not inputs you consume in production.

Category 3: Fuel- and energy-related activities

Emissions associated with producing the fuel and electricity you buy, that are not already counted in Scope 1 or 2. This includes the emissions from extracting, refining, and transporting fuel, plus transmission and distribution losses on the electricity grid.

Category 4: Upstream transportation and distribution

Emissions from transporting and distributing the products you buy, in vehicles you do not own or operate — typically your suppliers' inbound logistics and third-party carriers bringing goods to you.

Category 5: Waste generated in operations

Emissions from the treatment and disposal of waste your operations produce — landfill, recycling, incineration, wastewater treatment.

Category 6: Business travel

Emissions from employee travel for business in vehicles your company does not own — flights, trains, hotel stays, hire cars. This is often one of the more measurable categories for service businesses because expense records already capture most of the data.

Category 7: Employee commuting

Emissions from employees travelling between home and work. Increasingly relevant since hybrid working changed commuting patterns; some companies now also include the emissions of home working under this category.

Category 8: Upstream leased assets

Emissions from operating assets you lease (as the lessee) that are not already in your Scope 1 or 2 — for example, a leased warehouse whose energy you do not control directly.

The seven downstream categories (9–15)

Downstream emissions result from what happens to your product after you sell it.

Category 9: Downstream transportation and distribution

Emissions from transporting and distributing your sold products, where you do not pay for the transport — the logistics that move your goods onward to the end customer.

Category 10: Processing of sold products

Emissions from further processing of your products by other companies before they reach the final consumer. Relevant if you sell intermediate goods — components, ingredients, materials that a customer transforms.

Category 11: Use of sold products

Emissions generated when customers use the products you sell. For an energy-using product (a boiler, a vehicle, a machine), this is frequently the largest downstream category by a wide margin.

Category 12: End-of-life treatment of sold products

Emissions from disposing of your products once customers are finished with them — landfill, recycling, or incineration at the end of the product's life.

Category 13: Downstream leased assets

Emissions from operating assets you own and lease out to others (as the lessor), where those emissions are not already in your Scope 1 or 2.

Category 14: Franchises

Emissions from the operation of franchises — relevant only if you operate a franchise model, reported by the franchisor.

Category 15: Investments

Emissions associated with your investments — primarily relevant to banks, investors, and any business with significant equity or debt holdings.

Which categories actually apply to a UK SME?

Here is the practical reality: a typical UK SME does not measure all fifteen. The GHG Protocol itself does not require every category — it requires you to account for the categories that are relevant and material to your business and to explain any you exclude.

For most small UK suppliers, the categories that matter are:

Category	Likely relevant if…
1 — Purchased goods and services	You buy materials, components, or significant services (almost everyone)
3 — Fuel- and energy-related activities	You buy fuel or electricity (almost everyone)
4 — Upstream transportation	Suppliers deliver goods to you
5 — Waste	Your operations generate waste (almost everyone)
6 — Business travel	Employees travel for work
7 — Employee commuting	You have staff who commute
11 — Use of sold products	You sell an energy-using product
12 — End-of-life	You sell a physical product

Categories 2, 8, 9, 10, 13, 14, and 15 are often immaterial or zero for a small supplier, and it is entirely legitimate to say so — provided you say so explicitly rather than silently omitting them.

What your customer is usually asking for

When a large customer sends you a Scope 3 questionnaire, they are rarely asking you to report your own full fifteen-category footprint. In most cases they want:

Your Scope 1 and 2 emissions (which become their Category 1), and
A methodology statement so they can trust the number.

Occasionally a more advanced customer — particularly one reporting under ESRS E1 within CSRD or completing a CDP Supply Chain questionnaire — will ask for product-level carbon footprints or category-specific data. But the foundation is always the same: a credible Scope 1 and 2 number with a clear methodology. Get that right and you can answer the overwhelming majority of requests.

For the full workflow of responding to these requests, see our guide on Scope 3 supplier engagement.

Common mistakes when reporting Scope 3 categories

Trying to measure all fifteen. The standard rewards relevance and materiality, not exhaustiveness. Measuring the categories that matter, well, beats measuring all fifteen badly.
Confusing your Scope 1/2 with your Scope 3. If a customer asks for your Scope 1 and 2, do not include your own supply chain (your Scope 3) in the figure — that double-counts and inflates the number.
Silently omitting categories. If a category is immaterial or you cannot measure it, state that. An unexplained gap reads as an oversight; an explained exclusion reads as competence.
Using inconsistent boundaries year to year. Once you decide which categories you report, keep the boundary stable so figures are comparable. State any change.

Frequently asked questions

How many Scope 3 categories are there? Fifteen, as defined by the GHG Protocol Corporate Value Chain (Scope 3) Standard. Eight are upstream (categories 1–8) and seven are downstream (categories 9–15).

Which Scope 3 categories are upstream? Categories 1 to 8: purchased goods and services, capital goods, fuel- and energy-related activities, upstream transportation, waste, business travel, employee commuting, and upstream leased assets.

Do I have to report all 15 Scope 3 categories? No. The GHG Protocol requires you to account for the categories relevant and material to your business and to disclose which you have excluded and why. Most SMEs report only a handful.

Which Scope 3 category is usually the biggest? For product businesses, Category 1 (purchased goods and services) is typically the largest. For companies selling energy-using products, Category 11 (use of sold products) often dominates.

How AnswerVault will help

AnswerVault is designed to store your emissions data — including which Scope 3 categories you report, your figures, and the methodology behind them — as structured, reusable facts. When the next customer questionnaire asks for Scope 3 information, your pre-approved answers and supporting evidence are ready to reuse, with a record of which version went to which customer.

Try AnswerVault free to get started.

Sources

GHG Protocol Corporate Value Chain (Scope 3) Standard — World Resources Institute and World Business Council for Sustainable Development, Corporate Value Chain (Scope 3) Accounting and Reporting Standard, 2011. Defines the 15 categories of Scope 3 emissions (8 upstream, 7 downstream).
GHG Protocol Scope 3 Calculation Guidance — Technical Guidance for Calculating Scope 3 Emissions. Category-by-category calculation methods.
UK Government GHG Conversion Factors — published by the Department for Energy Security and Net Zero (DESNZ; formerly BEIS/DEFRA), Government conversion factors for company reporting of greenhouse gas emissions. The UK default factors for converting activity data to emissions.

This article provides general guidance for UK SMEs identifying which Scope 3 categories apply to their business. It is not accounting, audit, or legal advice. Category boundaries, materiality judgements, and calculation methodology should be reviewed against your customer's stated requirements and, where figures will be externally assured, with your accountant or auditor. The GHG Protocol Corporate Value Chain (Scope 3) Standard is the definitive reference.