Why only five?
The GHG Protocol splits Scope 3 into fifteen categories, from purchased goods to investments. Measuring all of them is a big job, so the Cabinet Office's technical standard for Carbon Reduction Plans picks five that almost any supplier can estimate from its own records, without waiting for data from its suppliers. If you want the full list, our guide to all 15 Scope 3 categories explains each one. This post is about the five you actually need for a PPN 006 plan.
The five categories in plain English
| Category | What it means for a small business | Where the data comes from |
|---|---|---|
| 4. Upstream transport | Goods delivered to you, and any delivery you pay a courier or haulier for, in either direction | Courier and haulier invoices: weight and distance |
| 5. Waste | Waste and recycling collected from your sites, and wastewater | Your waste contractor's reports; water bills |
| 6. Business travel | Trains, flights, taxis, hire cars, hotels and staff driving their own cars for work | Mileage claims, booking systems, expenses |
| 7. Employee commuting | Staff getting to and from work, and homeworking if you include it | A short staff survey |
| 9. Downstream transport | Delivery of the things you sell when you don't pay for it, such as customer collections | Estimated weights and distances; often "not applicable" for service firms |
The line between 4 and 9 is who pays, not which direction the goods travel. A courier you pay to deliver to a customer is category 4. Category 9 only covers transport your customer or someone else arranges and pays for.
A worked example for a 25-person firm
Here is a 25-person print and design business with one studio. It buys paper and ink by courier, recycles its offcuts, has staff who drive to client meetings and take the train to London, and some trade customers send their own hauliers to collect large orders. Every figure below uses the DESNZ 2026 conversion factors.
| Cat. | Source | Data | kg CO2e per unit | tCO2e |
|---|---|---|---|---|
| 4 | Paper and ink delivered by courier van | 4,000 tonne-km | 0.63511 per tonne-km | 2.54 |
| 5 | General waste to landfill | 3 tonnes | 520.58023 per tonne | 1.56 |
| 5 | Paper and card recycled | 6 tonnes | 4.65358 per tonne | 0.03 |
| 6 | Mileage claims in staff's own cars | 12,000 miles | 0.26699 per mile | 3.20 |
| 6 | Rail travel | 15,000 passenger-km | 0.03092 per passenger-km | 0.46 |
| 6 | UK hotel stays | 30 room nights | 10.4 per room night | 0.31 |
| 7 | Commuting by car (staff survey) | 60,000 miles | 0.26699 per mile | 16.02 |
| 7 | Homeworking | 10,000 FTE hours | 0.32393 per hour | 3.24 |
| 9 | Orders collected by customers' hauliers | 2,000 tonne-km by HGV | 0.10356 per tonne-km | 0.21 |
| Total for the five categories | 27.58 |
Factors are the main DESNZ 2026 factor for each activity. Well-to-tank emissions for the travel lines are left out to keep the example simple.
| Category | tCO2e |
|---|---|
| Category 4 | 2.54 |
| Category 5 | 1.59 |
| Category 6 | 3.98 |
| Category 7 | 19.26 |
| Category 9 | 0.21 |
What the example shows
Commuting is the big one. At 19.26 tonnes it is more than all the other categories put together. It also comes from data you won't find in your accounts, which is why it is the category people most often leave out. Our post on commuting without surveying everyone shows how to estimate it from a sample.
How waste is treated matters more than how much there is. Twice as much paper went to recycling as general waste went to landfill, yet the landfill line is far bigger, because landfill releases methane as waste breaks down. See waste emissions from your contractor's data.
Mileage claims belong in category 6. Staff driving their own cars for work are Scope 3 business travel, not Scope 1. Our post on company car and grey fleet emissions covers the difference.
Category 9 can be small and still worth reporting. The customer collections add little, but showing the row with a figure, rather than leaving it blank, tells the evaluator you checked.
If a category doesn't apply
Many service businesses have nothing in category 9, and some have nothing in category 4. That is fine. Put a short reason in the plan, such as "We sell professional services and do not ship goods to customers", rather than a zero with no explanation. Evaluators are looking for evidence that you considered each category.
How Carbon Recycling helps
Each activity you add is placed in its Scope 3 category for you, and freight asks who paid so it lands in 4 or 9 correctly. The Carbon Reduction Plan lists all five PPN 006 categories and shows "Not measured" for any you haven't covered yet, so gaps are obvious before you submit. Our PPN 006 guide covers the rest of the plan.