Scope 3 software comparison guide, and who is verified

You are being asked for a Scope 3 number you can defend, and there are more tools claiming to produce one every quarter. This guide groups the main options into four categories, says who each one is built for, and records what third-party verification each one has published.

Categories and verification status last reviewed 29 July 2026.

How should you compare Scope 3 software?

Compare on four things: coverage on the organisations you actually buy from or invest in, whether the calculation methodology has been verified by a named third party against a standard, whether the tool can go back to those organisations for better data, and whether the output is auditable when somebody checks it. Price and framework coverage matter too, and they rarely separate vendors the way these four do.

• Coverage: how much of your spend or portfolio the tool can put a number against before anyone collects new data.
• Verified methodology: a named verifier, a named standard, and a document you can open and read.
• Engagement: whether the tool can request, validate and reuse primary data from suppliers and portfolio companies.
• Auditability: whether every figure carries its source and change history, so a third-party auditor can follow it back.

The order below ranks the four categories by fit for supplier-driven and portfolio-driven Scope 3 work. That is one criterion, not a verdict on quality. A category ranked fourth here is the right choice for a different job, and several of the tools in it are the best in the market at that job.

Which Scope 3 platforms have third-party verified calculation methodology?

Five platforms had public third-party verification of their calculation methodology when we last checked: DitchCarbon, CarbonChain, Lune, Persefoni and Watershed. Our benchmark post, Who's Really Verified? A Reality Check on Carbon Software Assurance, names the verifier, the standard and the evidence for every vendor we checked, verified or not.

DitchCarbon is the only specialist Scope 3 tool with third-party assurance of its calculation methodology. The other four verified platforms are not specialist Scope 3 tools: two are full-inventory carbon accounting platforms, one is a calculation API and one is commodity-focused. The benchmark table is the evidence for that claim, so read it rather than taking our word for it.

Our own documents are public. The DitchCarbon Portal calculator is verified to ISO 14064-3, limited assurance, by UL Solutions, renewed annually. The emission factor methodology for spend-based Scope 3 categories 1 and 2 was independently assessed by Globus Thenken in August 2025. Both reports are downloadable from the DitchCarbon trust centre.

One distinction is worth holding on to while you compare. Verification of a vendor's software is not the same as assurance of that vendor's own corporate inventory, and neither is the same as a customer's report being assured. Ask which one you are being shown. Audit-ready is a phrase any vendor can print; ISO 14064-3 verification by a named verifier is the version your auditor can check.

Where an entry below says a vendor is not in our benchmark, it means we have not checked that vendor. It does not mean the vendor is unverified.

Specialist Scope 3 platforms (ranked 1)

Built for supply chain and portfolio emissions specifically: coverage on the organisations you buy from or invest in, engagement to improve the data, then planning on top of it.

1. DitchCarbon

DitchCarbon provides verified emissions data for over 2 million organisations, so procurement, sustainability and finance teams can measure and act on supply chain and portfolio emissions from one source. Matching runs on entity resolution against DUNS, LEI and ISIN identifiers, every figure carries its source and change history, and coverage gaps are shown rather than hidden. The Portal calculator is verified to ISO 14064-3, limited assurance, by UL Solutions, renewed annually.

The capability the platform is built around is engagement. Public and modelled data covers the long tail from day one, so requests go only to the organisations where a primary figure would change your total, prepopulated with what has already been published. That gets teams to numbers you can defend within 2 weeks, and in a recent deployment reached about 60% of a large supplier base within 2 weeks.

Who it's great for: procurement, sustainability and finance teams that need defensible coverage on their own suppliers or portfolio companies, and a route to better primary data without running another survey round.

2. StepChange

StepChange is built for centralised Scope 3 visibility across a large value chain, with a broad emission factor database and GHG Protocol aligned calculation. Deployment is quick. It is not in our verification benchmark.

Who it's great for: teams that want standards-aligned Scope 3 measurement across a wide value chain before they take on supplier-specific action planning.

3. Makersite

Makersite is built for product-level modelling: carbon, cost and compliance data against a bill of materials, so design and sourcing options can be compared part by part. It is not in our verification benchmark.

Who it's great for: product design and manufacturing teams comparing materials, processes and components at the part level.

Carbon accounting platforms (ranked 2)

Full-inventory platforms covering Scopes 1, 2 and 3 for corporate reporting. Strong on disclosure, and broader than Scope 3 by design.

1. Sweep

Sweep is a full-inventory carbon accounting platform with dashboards across Scopes 1, 2 and 3, plus supplier survey distribution. We checked Sweep for our verification benchmark and found no public software-level verification of its calculation methodology.

Who it's great for: ESG and sustainability teams that want one platform for company-wide emissions tracking and regulatory disclosure.

2. Watershed

Watershed is a full-inventory carbon accounting platform, known for its reporting quality and emission factor library. It holds ISO 14064-3 verification by Apex Companies, which makes it one of the five platforms in our benchmark with public third-party verification of its calculation methodology.

Who it's great for: enterprises that need clean, defensible inventory data across all three scopes for investor and regulatory disclosure.

3. Normative

Normative is a carbon accounting platform aligned to the GHG Protocol and EU reporting frameworks, used mainly by organisations preparing CSRD and CDP disclosures. We checked Normative for our verification benchmark and found no public software-level verification of its calculation methodology.

Who it's great for: European companies whose priority is compliance-aligned accounting and disclosure.

Lifecycle assessment software (ranked 3)

Product-level carbon modelling to LCA standards. High precision on one product, which is a different job from covering thousands of organisations.

1. Sphera

Sphera is enterprise LCA tooling, long established in industrial sectors, with detailed impact modelling across complex value chains and the GaBi factor sets behind it. Its supply chain product, Sphera SCS, was checked for our verification benchmark and we found no public software-level verification; the LCA tooling was not separately checked.

Who it's great for: companies that need deep environmental impact analysis and regulatory LCAs for products or materials.

2. OpenLCA / Ecoinvent

OpenLCA is open source LCA software, commonly run with the Ecoinvent database. It is flexible and free to licence, and it asks for LCA expertise and manual effort to use well. It is not in our verification benchmark.

Who it's great for: research teams and practitioners running bespoke product carbon assessments.

3. SimaPro

SimaPro is LCA software used widely by research institutions and design teams for granular product lifecycle modelling. It is not in our verification benchmark.

Who it's great for: engineering teams comparing trade-offs in product design and material sourcing.

4. One Click LCA

One Click LCA is built for construction and real estate, with templates aligned to building regulations and certification schemes. It is not in our verification benchmark.

Who it's great for: built environment teams meeting local building compliance or certification requirements.

Procurement platforms with sustainability features (ranked 4)

Sourcing and supplier risk platforms that carry ESG or carbon signals. Useful inside the buying decision, and built around supplier assessment rather than emissions calculation.

1. IntegrityNext

IntegrityNext is a supplier ESG and risk assessment platform used during sourcing and onboarding, including carbon screening questions. It is not in our verification benchmark.

Who it's great for: procurement teams adding ESG and carbon risk screening to supplier onboarding.

2. EcoVadis

EcoVadis is the best known supplier sustainability rating, with one consistent scorecard across a large supplier base and a rating many suppliers already hold. Ratings are the product rather than emissions calculation. We checked EcoVadis for our verification benchmark and found no public software-level verification of a calculation methodology.

Who it's great for: global procurement functions applying one ESG scorecard across their vendor base.

3. SAP Ariba and the sustainability add-on

SAP Ariba adds sustainability criteria to sourcing workflows that already run in SAP, which matters most where procurement lives in Ariba. SAP was checked for our verification benchmark and we found no public software-level verification of its carbon calculation methodology.

Who it's great for: SAP-native enterprises putting sustainability criteria into existing sourcing processes.

Comparison table, ranked by fit for supplier and portfolio Scope 3 work

Source note. Verification status comes from our benchmark post, Who's Really Verified? A Reality Check on Carbon Software Assurance, last checked 29 July 2026. Verified means we found public third-party verification of the vendor's calculation methodology, with the verifier and the standard named. Checked, none found means we looked for that evidence and could not find it published; the vendor may hold assurance that is not public, and assurance of a vendor's own corporate inventory is a different thing from verification of its software. Not in our benchmark means we have not checked that vendor, and nothing should be read into it either way. If anything here is out of date, tell us and we will correct it.

How do you test any of these against your own spend?

Whichever category you land in, the test is the same: how much of your own spend or portfolio the tool can put a defensible number against, and whether those numbers hold up when a third-party auditor follows them back to a source. DitchCarbon is a specialist Scope 3 carbon accounting platform, and the fastest way to judge it is against your own supplier list rather than a feature grid. See the coverage on your own supplier list.

If you landed here because a customer or an investor is asking you for emissions data, the quicker route is the other one: claim your company profile, answer once, and reuse it for every request that follows.