Scope 3 emissions — definition, 15 categories, examples
Scope 3 covers every indirect emission across a company’s value chain — 15 categories defined by the GHG Protocol, from the goods it buys to how customers eventually dispose of what it sells. For most companies it is the single largest scope. Here is each category with a real-world example, how to measure it, and the UK SRS S2 timing.
Scope 3 — every indirect emission across the value chain
Scope 3 is the GHG Protocol's catch-all for emissions a company causes without owning the source — split into 15 categories, 8 upstream and 7 downstream.
Defined by the GHG Protocol, not invented by UK SRS
Scope 3 emissions are defined by the GHG Protocol Corporate Value Chain (Scope 3) Accounting and Reporting Standard, published in 2011.
The 15 categories are mutually exclusive by design, to avoid double counting when several companies in the same value chain each report their own Scope 3.
UK SRS S2 adopts this taxonomy directly rather than defining its own.
For manufacturers and retailers, Scope 3 is usually dominated by Category 1 (purchased goods and services) and Category 11 (use of sold products).
For financial institutions, Category 15 (investments — financed emissions) typically dwarfs every other category combined.
There is no single “typical” Scope 3 profile: the categories that matter depend entirely on the business model, which is why the GHG Protocol requires companies to disclose which categories they assessed as material and why.
See Scope 1, 2 and 3 explained for how Scope 3 relates to the other two scopes.
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The 15 Scope 3 categories, with a real-world example for each
Categories 1–8 are upstream (before the product reaches the company); categories 9–15 are downstream (after it leaves).
| # | Category | Real-world example |
|---|---|---|
| 1 | Purchased goods and services | The steel, packaging and components a manufacturer buys in from suppliers to make its products |
| 2 | Capital goods | A new production line, a delivery van, or an office building the company purchases as a long-life asset |
| 3 | Fuel- and energy-related activities (not in Scope 1 or 2) | The emissions from extracting and refining the diesel a company burns, and grid transmission losses on its purchased electricity |
| 4 | Upstream transportation and distribution | A haulier delivering raw materials from a supplier’s warehouse to the company’s factory |
| 5 | Waste generated in operations | Landfill or incineration of offcuts, packaging waste and general office waste from the company’s own sites |
| 6 | Business travel | Employee flights, train journeys and hotel stays for work purposes, in vehicles the company does not own |
| 7 | Employee commuting | Staff driving their own cars, or taking the train or bus, between home and the office or depot |
| 8 | Upstream leased assets | A distribution centre a company leases from a landlord, where the landlord (not the tenant) controls the boiler and meter |
| 9 | Downstream transportation and distribution | A courier delivering a company’s finished goods from its warehouse to a retailer or a customer’s door |
| 10 | Processing of sold products | A food manufacturer selling a raw ingredient that a third-party bakery then processes into a finished product |
| 11 | Use of sold products | The electricity a customer uses to run a washing machine or a laptop over its lifetime after purchase |
| 12 | End-of-life treatment of sold products | A sold product being landfilled, incinerated or recycled once the customer discards it |
| 13 | Downstream leased assets | A shopping centre owner’s emissions from the units it leases out to retail tenants |
| 14 | Franchises | The Scope 1 and Scope 2 emissions of an independently-run franchise outlet trading under the parent company’s brand |
| 15 | Investments | A bank’s share of the emissions from the companies and projects it lends to or holds equity in — financed emissions |
Not every category will be material for every company.
The GHG Protocol Scope 3 Standard 1 recommends screening all 15 first, using rough spend-based estimates, before deciding which categories warrant deeper measurement.
Categories that are immaterial, have limited reduction potential, and are not central to the business model can be excluded from the detailed inventory — provided the exclusion and the reasoning behind it are disclosed.
Financial institutions applying Category 15 under UK SRS S2 use PCAF methodology 6 rather than the general Scope 3 calculation guidance, because financed emissions require a distinct attribution methodology.
Three measurement routes — in order of increasing accuracy
The GHG Protocol sets out a maturity path: start with spend-based estimates, move to activity-based data, and work toward supplier-specific figures for the categories that matter most.
- Spend-based methodLowest accuracy
- Applies an economic input-output emission factor (emissions per £ or $ spent in a given sector) to the money a company spent with a supplier. Requires only financial data, making it the fastest route to a first estimate — but it cannot distinguish between an efficient and an inefficient supplier in the same sector.
- Activity-based methodGHG Protocol recommended default
- Applies a physical-unit emission factor (e.g. kgCO2e per kilogram of steel, per tonne-kilometre of freight, per kWh of electricity) to the actual quantity of activity involved. More accurate than spend-based because it reflects real physical quantities rather than price, which can vary independently of emissions.
- Supplier-specific methodHighest accuracy
- Uses emissions data reported directly by the specific supplier or customer for the specific product or service in question — for example a supplier's own product carbon footprint. The GHG Protocol Scope 3 Standard treats this as primary data and the target for the highest-emitting, most material categories.
The GHG Protocol Technical Guidance 3does not require every category to reach supplier-specific accuracy — that would be disproportionate for immaterial categories.
The practical approach is to run spend-based estimates across all 15 categories first, then invest activity-based and supplier-specific effort only on the categories that screening shows are material.
UK SRS S2 requires disclosure of which data quality tier was used for each material category, so the measurement route chosen is itself part of the regulatory disclosure, not just an internal methodology decision.
Comply-or-explain — the one-year Scope 3 relief
Scope 3 is not exempt from UK SRS S2, but it is the one part of the standard given a transitional runway before disclosure becomes fully binding.
For the full data-quality hierarchy, financed-emissions methodology under PCAF, base-year and M&A treatment, and assurance readiness, see the dedicated UK SRS Scope 3 reporting guide.
Reduction routes — where the leverage actually sits
Because most Scope 3 emissions happen outside a company's own operations, the biggest reduction levers usually involve suppliers and customers, not internal efficiency projects alone.
A company's Scope 3 is, for the most part, someone else's Scope 1 and 2. Reducing it means changing what suppliers and customers do, not just what you do yourself.
The value-chain nature of Scope 3 reduction
Priority reduction levers by category: switching to lower-carbon suppliers or materials cuts Category 1 (purchased goods); extending product lifetimes, improving in-use efficiency, or designing lower-energy products cuts Category 11 (use of sold products) — often the largest single category for manufacturers of energy-using goods; designing for repair, reuse and recyclability cuts Category 12 (end-of-life treatment); and shifting from air to rail, or reducing travel volume altogether, cuts Category 6 (business travel).
Supplier engagement programmes — requesting primary emissions data, setting supplier-facing reduction targets, and offering capacity-building support to smaller suppliers — improve both data quality and actual emissions simultaneously, which is why the GHG Protocol and UK SRS S2 both treat supplier engagement as central rather than optional.
Carbon reporting software platforms with supplier data-collection workflows reduce the administrative burden of running these programmes at scale, particularly for companies with large, fragmented supplier bases where manual data requests do not scale.
Scope 3 emissions — frequently asked
Definition, categories, measurement and UK timing, answered directly.
What are Scope 3 emissions?
Scope 3 emissions are indirect greenhouse gas emissions that occur across a company’s value chain, both upstream (its suppliers) and downstream (its customers), but which the company does not directly own or control 1.
The GHG Protocol Corporate Value Chain (Scope 3) Accounting and Reporting Standard defines 15 categories covering everything from purchased goods to how a customer eventually disposes of a product.
For most companies, Scope 3 is the largest of the three scopes.
What are the 15 categories of Scope 3 emissions?
The 15 GHG Protocol Scope 3 categories 1 are: (1) purchased goods and services, (2) capital goods, (3) fuel- and energy-related activities, (4) upstream transportation and distribution, (5) waste generated in operations, (6) business travel, (7) employee commuting, (8) upstream leased assets, (9) downstream transportation and distribution, (10) processing of sold products, (11) use of sold products, (12) end-of-life treatment of sold products, (13) downstream leased assets, (14) franchises, and (15) investments.
Categories 1–8 are upstream; categories 9–15 are downstream.
How do you measure Scope 3 emissions?
The GHG Protocol Technical Guidance 3 sets out three broad measurement routes, in ascending order of accuracy and effort.
Spend-based multiplies money spent by an average emissions-per-pound factor — fast, but imprecise.
Activity-based multiplies actual physical activity (kilograms of material, kilometres travelled, kilowatt-hours used) by an emission factor specific to that activity — more accurate, and the recommended default once spend-based screening has identified the material categories.
Supplier-specific uses primary data supplied directly by the supplier or customer for the exact product or service — the most accurate, but requires supplier engagement and data-sharing.
Is Scope 3 reporting mandatory in the UK?
Not universally, and not yet in full.
SECR does not require a full Scope 3 inventory.
UK SRS S2 4 does require Scope 3 disclosure for in-scope listed companies, but on a comply-or-explain basis with a one-year transitional relief, biting for financial years beginning on or after 1 January 2028 5.
Companies not directly in scope of UK SRS S2 are still commonly asked for Scope 3 data by customers who are — because a supplier’s Scope 1 and 2 emissions are that customer’s Scope 3.
How can a company reduce Scope 3 emissions?
The starting point is screening all 15 categories to find which are material, then engaging the highest-emitting suppliers directly rather than trying to improve every category at once.
Common reduction levers include: switching to lower-carbon suppliers or materials (Category 1), extending product lifetimes and improving efficiency in use (Category 11), redesigning products for easier recycling (Category 12), and shifting business travel to lower-carbon modes (Category 6).
Because most Scope 3 emissions sit outside the company’s own operations, supplier and customer engagement — not internal efficiency measures alone — is usually the largest lever available.
What is the difference between Scope 3 and Scope 1 or 2?
Scope 1 and Scope 2 cover emissions from sources the company directly owns, controls or purchases energy from.
Scope 3 covers everything else — emissions caused indirectly by the company’s activities but generated by other organisations in its value chain, such as suppliers, logistics providers, franchisees and customers.
See the Scope 1, 2 and 3 explainer for the full definitional comparison.
Scope 3 in the wider UK climate-reporting stack
From the foundational scope definitions through to UK SRS S2 compliance and financed emissions.
Scope 1, 2 and 3 emissions explained
Plain-English definitions of all three scopes and how Scope 1 differs from Scope 2.
UK SRS RequirementsUK SRS Scope 3 reporting guide
Data quality hierarchy, PCAF financed emissions, base-year treatment and assurance readiness.
StandardsThe GHG Protocol explained
What the GHG Protocol is, its global authority, and the revision underway to 2027.
ImplementationCarbon reporting software
Platforms with supplier engagement and Scope 3 data-collection workflows.
Related guides & references
Scope 1, 2 and 3 Emissions Explained
Plain-English definitions of all three scopes, the difference between Scope 1 and Scope 2, and how SECR and UK SRS S2 differ.
UK SRS Scope 3 Reporting Guide
Data quality hierarchy, financed emissions under PCAF, and the comply-or-explain timeline for UK SRS S2 Scope 3.
The GHG Protocol: the standard behind UK SRS emissions
What the GHG Protocol is, its authority, and the corporate-suite revision underway.
Scope 3 Category 15: financed emissions
Dedicated uksrs.finance guide to Category 15 investments — PCAF asset classes, attribution factors and data-quality scoring.
Complete Scope 3 Emissions Inventory
Step-by-step guide to building a Scope 3 inventory across all 15 categories, with calculation examples and data sources.