The 5 mandatory Scope 3 categories under PPN 006

The GHG Protocol splits Scope 3 — your indirect, value-chain emissions — into fifteen categories. PPN 006 selects five that are relevant to almost every supplier and measurable without a full supply-chain audit. Here is what each covers, with a concrete example for a smaller business.

• Category 4 — Upstream transportation and distribution. Emissions from moving goods and materials to you, where you pay for the transport. Example: you pay a courier or haulier to deliver your supplies, or a pallet firm brings stock into your unit. The vehicle is operated by someone else, but the journey is bought by you.
• Category 5 — Waste generated in operations. Emissions from treating and disposing of the waste your operations produce. Example: your general waste, dry mixed recycling and any hazardous waste collected from your premises and sent to landfill, recycling or incineration.
• Category 6 — Business travel. Emissions from staff travelling for work in vehicles you do not own. Example: an employee takes a train to a client meeting, flies to a conference, or claims mileage for using their own car on a site visit. Hotel nights are commonly reported here too.
• Category 7 — Employee commuting. Emissions from staff travelling between home and their usual workplace. Example: your team driving, taking the bus or cycling to the office each day. Energy used while home-working is increasingly reported under this category as well.
• Category 9 — Downstream transportation and distribution. Emissions from moving your sold products onward to customers, where you do not pay for the transport. Example: a customer arranges their own collection, or a distributor ships your product to the end buyer at their cost.

If you are new to the three scopes, our guide on calculating Scope 1, 2 and 3 emissions sets out how they fit together before you tackle the five categories.

For every category the goal is activity data — a real quantity you can multiply by a DEFRA conversion factor. Where activity data is unavailable, a spend-based estimate is an accepted fallback (covered below). The table shows the practical inputs an SME needs, and a spend-based alternative for each.

DEFRA publishes both activity-based and spend-based factors, so you can start with whatever you have to hand and refine later. The conversion factors that turn each of these inputs into tonnes of CO2e are covered in our DEFRA emission factors guide.

A handful of errors account for most of the queries assessors raise on the Scope 3 section of a Carbon Reduction Plan. Watch for these.

• Confusing Category 4 and Category 9. The test is who pays for the journey. Inbound transport that you pay for is Category 4; onward movement of goods you have sold, where the customer or distributor pays, is Category 9. Getting this backwards is the single most common Scope 3 mistake.
• Forgetting employee commuting. Category 7 is easy to skip because there is no invoice for it. A short staff survey covering distance, mode and days on site is enough to produce a defensible estimate — leaving it blank is not.
• Double-counting your owned fleet. If you own or lease the vehicles and buy the fuel, those emissions are Scope 1, not Scope 3. Reporting the same van under both Scope 1 and Category 4 or 6 double-counts and inflates your total.
• Treating 'not applicable' as 'ignore'. You must still address all five categories. If one genuinely does not apply, mark it not applicable with a short note — do not silently drop it.
• Mixing factor years. Use a single DEFRA factor vintage across all five categories so your numbers reconcile. Mixing years, or using out-of-date factors, undermines the whole plan.

CarbonPass builds the five PPN 006 Scope 3 categories from three inputs, then formats them to the standard set by the Government Commercial Agency (GCA, formerly Crown Commercial Service).

• Bills. Upload your utility, fuel and waste bills and the platform extracts the activity data — kWh, litres, tonnes of waste — and routes each line to the correct scope and category.
• Guided questions. For categories with no bill behind them — business travel and employee commuting in particular — short guided questions fill the gaps, such as commute distances, rail and air journeys, and mileage claims.
• DEFRA factors. Every input is converted using the current-year UK Government DEFRA conversion factors, applied consistently across all five categories.

Where you only have annual spend for a category, CarbonPass uses DEFRA's spend-based factors as a fallback and clearly flags those lines as estimates in the plan, so a buyer can see exactly which figures are measured and which are approximated. The result is a Carbon Reduction Plan that addresses all five Scope 3 categories alongside full Scope 1 and Scope 2, in the format the GCA Carbon Reduction Plan technical standard requires — and that buyers such as NHS England's Greener NHS programme expect to see from their suppliers. You can read the underlying method on our methodology page.

Do I need to report all 15 Scope 3 categories?

No. The GHG Protocol defines fifteen Scope 3 categories, but PPN 006 requires only five of them: Category 4 (upstream transportation and distribution), Category 5 (waste generated in operations), Category 6 (business travel), Category 7 (employee commuting) and Category 9 (downstream transportation and distribution). These sit alongside full Scope 1 and Scope 2 reporting. You can voluntarily report additional categories, but the five plus Scopes 1 and 2 are what a compliant Carbon Reduction Plan must cover.

What if one of the five categories does not apply to my business?

You still have to address it. If a category genuinely does not apply — for example, you sell a service and arrange no downstream distribution — report it as not applicable or zero with a short note explaining why, rather than leaving it out. Buyers and assessors want to see that you have considered all five categories, so an explicit "not applicable, because..." is treated very differently from a silent omission.

Can I use spend-based estimates instead of activity data?

Yes, where activity data is unavailable. The preferred approach is activity data (litres of fuel, tonnes of waste, kilometres travelled), but DEFRA also publishes spend-based conversion factors that turn annual pounds spent into an emissions estimate. Spend-based figures are an accepted fallback provided they are clearly flagged as estimates so the reader knows which lines are measured and which are approximated.

Which DEFRA emission factors should I apply?

Use the current-year UK Government DEFRA conversion factors (the "Government conversion factors for company reporting" dataset, published annually, usually in June). Apply the set that covers your reporting period, and use the same vintage consistently across all five categories so your totals reconcile. Mixing factor years, or using out-of-date factors, is a common reason a Carbon Reduction Plan is queried.