Scope 3 covers everything in a company’s value chain outside its own operations: what it buys, how goods move, how staff travel, and what happens when customers use and throw away its products. It is often the largest part of a footprint, and the hardest to cut, because someone else controls the source.
This guide is part of our business emissions section, within the wider carbon footprint guide. For the 15 categories and what each covers, see scope 1, 2 and 3 explained.
Why scope 3 matters
Companies reporting to CDP said their supply chain emissions were on average 26 times their operational emissionsSource 3. A plan that only covers scope 1 and 2 misses most of the picture for many companies.
The SBTi builds this into its rules. When scope 3 is 40% or more of total scope 1, 2 and 3 emissions, near-term targets must cover at least 67% of scope 3, and long-term targets 90%Source 2.
Step 1: find the hot spots
The Scope 3 Standard describes the most rigorous way to prioritise: estimate every scope 3 activity with initial screening methods, such as industry-average or input-output data, then rank them from largest to smallestSource 1. The result shows the “hot spots” where reduction efforts will do the mostSource 1.
A spend-based screen is a fast start. Multiply what you spend in each category by a per-pound or per-dollar factor, such as Defra’s multipliers in the UKSource 4. It won’t be precise, but it shows where to look.
The SBTi lists the categories likely to matter most by sectorSource 2:
Scrolls sideways to show every column.
| Sector | Likely hot spot |
|---|---|
| Consumer packaged goods | Purchased goods and services (category 1) |
| Food processing | Purchased goods and services (category 1) |
| Logistics | Upstream transportation and distribution (category 4) |
| Automotive | Use of sold products (category 11) |
| Electronics | Use of sold products (category 11) |
| Gas distribution and retail | Use of sold products (category 11) |
| Chemicals | End-of-life treatment of sold products (category 12) |
As of Oct 2026 · Source: [2] SBTi Corporate Net-Zero Standard v1.3.1
Step 2: get better data
Screening uses secondary data: industry averages, government statistics, published databases, financial data and proxies. Primary data comes from suppliers or other value chain partners about the specific activities in your chainSource 1.
Better data matters because averages can’t show a supplier’s improvements. If a supplier halves its emissions but you still apply an industry-average factor to what you spend with it, your scope 3 doesn’t move. Move your largest categories to supplier data first.
Step 3: engage suppliers
For many companies, a main goal of a scope 3 inventory is to encourage suppliers to measure and cut their emissions. The Scope 3 Standard describes engaging major suppliers to get emissions data on the products bought from them and on their GHG management plansSource 1.
Step 1: Prioritise
Pick the suppliers behind your largest hot spots, often a small share of your supplier list.
Step 2: Ask for data and plans
Request product-level emissions data, an inventory and whether they have reduction targets.
Step 3: Build it into buying
Add emissions criteria to tenders and contracts, and favour suppliers with credible targets.
Step 4: Support and track
Share tools and guidance, agree milestones, and report progress each year.
The SBTi allows supplier or customer engagement targets as part of near-term targets. The company states what share of emissions, or of procurement spend, the target covers; the suppliers or customers must have science-based targets within at most five years of submission; and the SBTi recommends 2030 or earlier as the target yearSource 2.
Step 4: redesign and rethink
Supplier engagement isn’t the only lever. Depending on your hot spots:
- Purchased goods: use less material, switch to lower-carbon inputs, and buy fewer, longer-lasting items.
- Transport and logistics: consolidate loads, shift to rail or sea, and work with carriers on cleaner fleets.
- Business travel and commuting: rail before short flights, economy by default, and support for public transport and cycling.
- Use of sold products: design for energy efficiency, since what customers use affects your category 11.
- End of life: design for repair, reuse and recycling.
The Scope 3 Standard also describes working with customers, for example on more efficient use and on recycling, using the inventory to identify downstream hot spotsSource 1.
Set a scope 3 target
On the SBTi’s cross-sector pathway, the minimum ambition for near-term scope 3 targets is a linear cut of 2.5% a year, against 4.2% for scope 1 and 2Source 2. Targets can combine absolute reductions, intensity reductions and engagement targets, as long as together they reach the coverage thresholdSource 2.
Credits don’t reduce scope 3
Buying carbon credits doesn’t lower your scope 3. The SBTi requires credits to be reported separately from the inventory and never counted as progress towards targetsSource 2. See residual emissions for where credits fit at net zero.
Common pitfalls
- Waiting for perfect data. Screening estimates are enough to rank categories and start work; improve the data for the largest ones as you goSource 1.
- Spreading effort thinly. Asking every supplier for everything produces little. Concentrate on the few behind your hot spots.
- Counting spend cuts as climate progress. With spend-based factors, buying less of the same thing lowers your estimate, but so does a price drop. Track physical quantities and supplier data where you can.
- Forgetting the downstream. For some sectors, such as automotive and electronics, use of sold products is the likely hot spotSource 2.
Next steps
Pull scope 3 into your wider plan with reducing company emissions and the net-zero plan guide.