Scope 3 software for large supply chains: 6 platforms compared (2026)

Scope 3 software for large supply chains is judged on the suppliers nobody has time to chase. Six platforms compared on what holds up as the list grows from thousands of suppliers to over 100,000, and what that gets you: a baseline you can act on, fewer requests to suppliers, and hours back for the team. For what each platform automates, see automated supplier emissions tracking compared; for the method behind managing 5,000 or more suppliers, see Scope 3 data collection across 5,000 or more suppliers.

Vendor features checked against each vendor's public pages on 30 October 2026.

How do large companies track Scope 3 across thousands of suppliers without doing it manually?

They start from the data that already exists and send requests only where a better figure would change the total. On a list of 5,000 or 100,000 suppliers, the manual work sits in three places: matching each name in the purchase file to the right organisation, finding a figure for each one, and chasing replies. DitchCarbon does the first two before anyone is asked. It matches the list against verified emissions data for over 2 million organisations, built on primary emissions data wherever it exists, using DUNS, LEI or ISIN where the file carries them and a company name alone where it does not, and returns a ranked list the same week. A recent deployment reached 70% coverage of emissions with primary data within 2 weeks.

The chasing shrinks with it. Requests go from the platform to the suppliers that matter by emissions, prepopulated with what each has already published, so the supplier adds only the detail the buyer needs. A recent deployment gained additional primary data from 30% of over 40,000 recipients. Every reply type (a report, a site's energy figures, activity data, a product carbon footprint) is read into the same record, so the method is the same for 100 suppliers as for 100,000.

On a platform whose supplier data arrives by collection, each of those three jobs grows with the list: more names to map, more forms to send, more replies to chase, and every supplier who has not answered stays on an industry average. DitchCarbon keeps the team's hours on the suppliers that matter, whatever the size of the list.

Can you run DitchCarbon alongside Watershed, Sweep or Persefoni?

Yes. Watershed, Sweep and Persefoni are systems of record for the full inventory and the disclosure. Run alongside one of them, DitchCarbon becomes the data layer feeding it: each supplier matched and calculated by the most accurate method available, with the source behind each figure, before the inventory platform sends its first request. Run on its own, DitchCarbon is the platform and the system of record for Scope 3. It measures, engages, forecasts each supplier against its own target trajectory and tracks progress at category, portfolio or account level, and it integrates into the procurement, ERP or sourcing system the team already runs.

Which Scope 3 platforms hold up on supply chains of over 100,000 suppliers?

On a large supply chain, the purchase file often holds nothing but supplier names. DitchCarbon matches from a name alone, with DUNS, LEI or ISIN raising the match rate where the file carries them, so the whole list is in play from the first upload.

How do the 6 platforms compare at scale?

1. DitchCarbon

DitchCarbon is a specialist Scope 3 carbon accounting platform built for large supply chains, and it runs in production on supply chains of over 100,000 suppliers. The purchase file goes in as it is: a spend export at minimum, with quantities and product codes where available, and no cleanse or integration project. Each supplier is matched by entity resolution against DUNS, LEI and ISIN identifiers, or from a company name alone where that is all the file holds, then calculated with a hybrid calculation: product data, activity data and supplier-specific spend, and only when all else fails, industry-level spend. Every line records which method produced it, so the share still on an industry factor is a number the team can watch fall.

AI reads what suppliers have already published and a team of 15 analysts checks it, so the team's hours go on decisions. The four-step maturity ladder, sorted against embodied emissions, decides who is worth asking. Requests go out prepopulated, and a supplier that claims its free profile answers once for every buyer who asks. Numbers you can defend within 2 weeks is the timeline for the baseline, and each supplier is then forecast against its own target trajectory, rolled up to category, portfolio or account level. Every figure carries its source and change history, and the Portal calculator is verified to ISO 14064-3, limited assurance, by UL Solutions, renewed annually.

Best for: large enterprises that want to act on supply chain emissions this year without a survey programme sized to the list. Most of the list is covered before the first request, the requests that do go out are small, and the team's hours go on the suppliers that matter.

2. Watershed

Watershed engages suppliers "at scale" through "built-in workflows, supplier portals, and scorecards", ranks them by emissions impact and climate maturity, and enriches the picture from "tens of thousands of supplier disclosures, auto-mapped". Supplier responses replace industry averages in the footprint, so the primary share of the baseline follows the number of replies. DitchCarbon matches the whole list against verified emissions data for over 2 million organisations before a request goes out, and where Watershed is already the inventory platform, DitchCarbon feeds it as the specialist Scope 3 layer.

Best for: companies that put one platform for inventory and suppliers ahead of the load on suppliers: on a list of 100,000, every supplier who has not replied through the portal stays on an industry average.

3. Sweep

Sweep is a full-inventory carbon accounting platform whose supplier module promises "100% supply chain coverage from day one", with collection methods that run "from sectoral estimates, to verified declared data". It imports from CDP Supply Chain, EcoVadis, S&P and the SBTi, runs surveys and supplier portals with "automated reminders", gives every surveyed supplier a free account, and points the effort at "the 20% of suppliers driving 80% of emissions". Run alongside Sweep, DitchCarbon supplies a supplier-specific figure for each matched supplier from the start, calculated by the most accurate method available for each line.

Best for: ESG teams that want one tool for every scope and broader ESG data, with supplier surveys and reminders run from it.

4. Persefoni

Persefoni gives suppliers free Persefoni Pro accounts to measure their own carbon footprint, and lists a Scope 3 Data Exchange for requesting and receiving supplier data as coming soon. Its supplier engagement page does not describe how suppliers are prioritised, matched or chased, so across a large list each figure arrives once that supplier has built its own footprint. DitchCarbon holds the figure the supplier has already published, so a Persefoni inventory can start from it on day one, with DitchCarbon running alongside as the supplier layer.

Best for: finance-led companies that run the inventory and disclosure on Persefoni and can wait for suppliers to build their own footprints.

5. Normative

Normative "automates data requests, tracks responses, and validates submissions". Its route to supplier figures runs through surveys, a shared Carbon Network for PCF and EPD data, an EcoVadis integration and its own analysts researching your most important suppliers, with Climate Strategy Advisors setting criteria and prioritising outreach. Greenly announced its acquisition of Normative in September 2026 and says Normative's methodology now feeds Greenly's own platform. That reach grows with the number of suppliers someone has chosen to research. Normative's own large-base example is a customer with over 10,000 active suppliers; DitchCarbon covers supply chains of over 100,000 from verified data before anyone is chosen, with the source document behind every figure, and asks only where a better figure would change the total.

Best for: companies whose list of key suppliers is short enough for advisers and analysts to work through by hand.

6. Greenly

Greenly is a carbon accounting platform for every scope, built around smaller companies: its funding announcement states the mission as helping "SMBs measure, report and reduce the carbon footprint of their operation and supply chain", and it prices itself from £15k, "without the enterprise price tag". It acquired Normative in September 2026. Its supplier module checks a list against its own supplier database and public reports before any questionnaire goes out, then sends pre-filled questionnaires through a supplier portal to the suppliers with data gaps. DitchCarbon is built for large supply chains: it runs in production on supply chains of over 100,000 suppliers, matches each one by DUNS, LEI, ISIN or name alone, and gives a large organisation numbers it can defend within 2 weeks, with a calculator verified to ISO 14064-3 by UL Solutions.

Best for: smaller supply chains.

How should you test a Scope 3 platform on a large supplier list?

Send each vendor a sample of your purchase file exactly as it leaves the ERP, including the rows that carry nothing but a supplier name, and ask for three numbers: how many suppliers were matched, how many carry a figure before any request goes out, and what share of the baseline still rests on an industry average. The first two are the work your team will not have to do. The third is what the requests still have to close. DitchCarbon shows all three as numbers, because every line records the match and the method that produced it.