Scope 3 software: method before number
A Scope 3 inventory may combine secondary estimates and primary data. The GHG Protocol does not prescribe one universal ladder: it provides category-specific methods and asks companies to choose for each activity using relative emissions, business goals, data availability and quality, and the cost and effort of applying the method. This guide tests whether software preserves those choices and their evidence.
Jump to the 12 products
Editorial responsibility: Dimitris Mitsios (Founder of The QHSE Standard; product marketing at Tekmon) · Tekmon pays for sponsored placements on this site (disclosure) · How pages are made · LinkedIn · Content date: 27 September 2026
TekmonAd
Explore its published safety, quality and maintenance workflows. Confirm modules and pricing in a scoped proposal.
On this page (10 sections)
The method decides what the number is good for
The GHG Protocol's Corporate Value Chain standard defines fifteen Scope 3 categories. Category coverage alone does not establish which calculation method or inputs were used, their quality, or whether they are suitable for the intended decision. GHG Protocol: Corporate Value Chain (Scope 3) Standard
The Technical Guidance says to select a calculation method for each Scope 3 activity within a category using criteria that include relative emissions size, business goals, data availability, data quality, cost and effort, and other company-specific considerations. It ranks methods within categories by specificity and says more-specific methods generally produce higher-quality data; it does not make the most specific method a universal first choice. GHG Protocol: Technical Guidance for Calculating Scope 3 Emissions
An inventory may mix methods across categories and activities. The software question is whether it records the method and input source behind each result, preserves changes and supports a controlled restatement when the method, factor or source data changes. Ask to compare two valid methods for one activity and keep both calculation histories visible.
If a science-based target is the destination, the target framework's own requirements govern what your inventory has to demonstrate, independently of any platform. Establish those first and treat the software as the means of evidencing them. Science Based Targets initiative
The fifteen categories, upstream and downstream
| Category | What it covers | Direction |
|---|---|---|
| 1. Purchased goods and services | Production of the goods and services the company buys; usually where a first screening starts | Upstream |
| 2. Capital goods | Production of equipment, buildings and other capital assets bought | Upstream |
| 3. Fuel- and energy-related activities | Extraction, production and transmission losses of fuel and energy, where not already in Scope 1 or 2 | Upstream |
| 4. Upstream transportation and distribution | Transport of purchased products to the company, and other transport it pays for | Upstream |
| 5. Waste generated in operations | Disposal and treatment of the company's operational waste by third parties | Upstream |
| 6. Business travel | Employee travel for work in vehicles the company does not own or operate | Upstream |
| 7. Employee commuting | Employees travelling between home and work | Upstream |
| 8. Upstream leased assets | Operation of assets the company leases, where not already in Scope 1 or 2 | Upstream |
| 9. Downstream transportation and distribution | Transport of sold products that the company does not pay for | Downstream |
| 10. Processing of sold products | Further processing of intermediate products by the buyer | Downstream |
| 11. Use of sold products | Customers' use of the products sold; large for energy-using products | Downstream |
| 12. End-of-life treatment of sold products | Disposal and treatment of sold products at end of life | Downstream |
| 13. Downstream leased assets | Operation of assets the company owns and leases to others | Downstream |
| 14. Franchises | Operation of franchises, reported by the franchisor | Downstream |
| 15. Investments | Emissions associated with investments, including equity and debt | Downstream |
Three things that differ, beyond category coverage
Data quality and restatement
How the platform records which method produced each figure, how it scores data quality, and what happens to last year's number when this year's method improves. Assurance turns on the audit trail here, not on the total.
Supplier engagement
Nearly every vendor scopes this separately from the calculation engine. Establish whether the platform sends questionnaires, chases responses, and validates what comes back — or whether that is a service line, or your job.
Emission factor provenance
Which factor databases are used, which version, who updates them and what happens to your historic figures when a factor changes. A recalculated past is a disclosure problem if you cannot explain it.
Where each vendor's documented scope ends
Several profiles scope supplier engagement, APIs or advisory work separately from calculation, but the boundary differs by product. Each note records where that product's own documentation draws the line; not ranked, not equivalents, and no product was tested hands-on.
Tekmon pays for a sponsored placement (above); its place in this list follows the same rule as every entry. How lists are ordered
Same rule for every product: tagged “Carbon Accounting”, “Carbon Management”, “Scope 3” or “Emissions Reporting”, with a sourced Scope 3 or supplier-emissions capability in its record, or one the vendor stated to us, labelled as vendor-stated. 12 qualify; the first 8 are shown here. The directory below continues with the other 4 tagged profiles, 4 of which also meet the rule.
Greenly
Corporate GHG assessment and supplier engagement are documented. LCA, wider ESG, API, SSO and services are each scoped separately, so a product footprint requirement is a different conversation. Source: greenly.earth
Normative
Corporate carbon accounting, supplier engagement and product footprints are documented, with reporting and advisory scope confirmed separately. Ask which parts are software and which are people. Source: normative.io
Persefoni
Pro covers an initial organizational inventory; Advanced is for more configurable programmes. Reporting exports, connectors and financial-services specifics must be named in the agreement rather than assumed from the tier. Source: persefoni.com
Plan A
Documented: Supplier data (Supply Chain+) (conditional). Source: plana.earth
Sweep
Corporate carbon and ESG records, supplier data collection, disclosure governance and decarbonisation planning. Establish how supplier-provided data is distinguished from estimated data in the same report. Source: sweep.net
Watershed
Measurement and disclosure preparation are the documented core. Supplier engagement and related services are scoped separately — establish whether chasing your suppliers is included or is a service line. Source: watershed.com
Microsoft Sustainability Manager
Carbon, water and waste data management, with calculation, reporting and value-chain capabilities dependent on the plan. The value-chain capability is the plan-dependent part and is the one Scope 3 turns on. Source: learn.microsoft.com
Tekmon
Documented: Supplier-based Scope 3 data collection. Source: tekmon.com
Run one category through the whole process
Bring your own procurement extract
Use a real category — purchased goods and services is the usual worst case. A demonstration on the vendor's sample data proves nothing about how your ledger maps to their categories.
Compare two Category 1 methods
Use two methods that the Category 1 guidance permits for the same activity. Confirm the platform records why each method was selected and that both histories can coexist rather than one silently overwriting the other.
Test supplier-data quality and allocation
Add supplier product data and establish whether it is sufficiently complete for the business goal, how shared emissions are allocated, how it is distinguished from secondary data and what happens after a supplier revision.
Change an emission factor and restate
Update a factor version and ask to see the prior year restated, with the reason recorded. If the history silently changes, you cannot explain the movement to an assurer.
Export what an assurer would ask for
Produce the figure, its method, its data source, its factor version and its date as one traceable set. Confirm it is readable without a licence to the platform.
Questions that separate candidates
Sources and evaluation limits
4 sources
Category structure and calculation methods: GHG Protocol: Corporate Value Chain (Scope 3) Standard; organisational boundary and the scopes themselves: GHG Protocol: Corporate Standard; target requirements, which sit outside any platform: Science Based Targets initiative; Category 1 calculation methods: GHG Protocol: Technical Guidance for Calculating Scope 3 Emissions.
We do not publish a figure for the share of a footprint that Scope 3 represents. The often-quoted range is not something we have measured, and it varies so widely by sector that a single number is of little use in a buying decision — a heavy manufacturer and a professional services firm are not in the same conversation. Establish your own split from a first inventory before letting it drive scope.
Product notes are drawn from each profile's researched sources, each linked with its source; the profiles carry the check dates. Vendor documentation describes intended scope, not observed behaviour; nothing here was tested hands-on, no product is ranked, and this is not a complete market survey. Treat the scope boundaries as the questions to put into a written proposal.
More researched products for this process (4)
The rest of the list above: every other catalogue profile meeting the same tag-and-capability rule, in the same order, checked against the vendor's own documentation on the date shown. Not a recommendation or a complete market map; confirm the module and workflow with the vendor.
Software categories to explore
Use this Process to define the work, then explore these software types. Confirm the exact workflow and module with each vendor.
See all software categoriesRelated Guides
More related guides
- Scope 3 Emissions in 2026: Data Strategy & Software Playbook
Article on Scope 3 emissions data.
- GHG Scope 1, 2 and 3 — definition, software & FAQs
Definition of GHG Scope 1, 2 and 3.
- Carbon Accounting Software for Enterprise: Buyer Shortlist
Shortlist guide for carbon accounting at enterprise scale.
- Scope 3 Emissions — definition, software & FAQs
Definition of Scope 3 emissions.
- SBTi (Science Based Targets initiative) — definition, software & FAQs
Definition of the SBTi.