The best carbon accounting software in Australia for AASB S2 (2026)

An assurance provider reviews your first AASB S2 report before your directors sign it. That changes the software question. You are choosing a system that can show an assurer where each Scope 1 and 2 figure came from in your first reporting year. A year later it has to do the same for Scope 3, and the year after that to a higher standard of evidence.

AASB S2 is the climate standard inside the Australian Sustainability Reporting Standards (ASRS). Group 1 companies report for financial years starting on or after 1 January 2025, Group 2 from 1 July 2026 and Group 3 from 1 July 2027.

We make one of the eight platforms below, and we have put it first. Read that placing with the bias in mind. We describe the other seven from their own websites and the 2026 analyst reports, and we say who each one fits. The questions to take into a demo are at the end.

The eight platforms at a glance

For the size thresholds and start dates for each group, see our guide to Australia's climate disclosure rules.

The eight platforms assessed

1. Terrascope

Best for: food, agriculture, CPG and retail companies with complex, land-linked supply chains that need audit-ready carbon measurement in weeks.

Terrascope measures Scope 1, 2 and 3 emissions and reaches an audit-ready baseline in four to six weeks for standard corporate measurement. Finance exports and supplier spreadsheets go in as they are. Machine learning matches each line to an emission factor, using Australian factors where they exist.

Ernst & Young has assured the methodology, and each figure keeps its lineage back to the bill or invoice it came from. Dyno Nobel, the explosives group headquartered in Brisbane, used that trail to complete limited assurance over 1.6 million tonnes of Scope 1 and 2 emissions across five continents, a full year before its ASRS deadline.

For the report itself, Terrascope's climate reporting module maps the 86 disclosure requirements of IFRS S2, the standard AASB S2 is built on. It drafts a response to each one from your own documents and the carbon data in the platform. Your editors and reviewers approve or change each draft, and the export carries the audit trail with it.

Scope 3 arrives in your second year, and for a food or agricultural business most of it sits upstream, on farms. Terrascope calculates product carbon footprints for thousands of products without supplier data. Vitasoy used its footprints to show emissions 16% below the industry benchmark, and took that into sales conversations ahead of mandatory reporting in Australia.

Terrascope's climate and carbon specialists work with your team from the first data upload to the conversation with your assurer. They are part of the subscription.

2. Avarni

Best for: mid-market companies and finance teams reporting under ASRS for the first time.

Avarni was built in Australia for ASRS and AASB S2, and it sells to the finance team rather than the sustainability team. It pairs the software with guided set-up, states a 100% audit pass rate across its clients, and integrates with more than 1,000 enterprise systems. BDO Australia is a partner. Avarni gives away a large library of AASB S2 templates and checklists, which is worth knowing even if you buy elsewhere.

3. Sumday

Best for: finance teams that want emissions accounted for like financial transactions.

Sumday is Australian and was built by accountants, which shows. Its carbon ledger codes each transaction to an emissions source, so the footprint reconciles to the general ledger. The AI drafts board papers and disclosures for AASB S2, ISSB, CSRD, TCFD and NGER, and Sumday will run your supplier engagement programme for Scope 3. It holds ISO 27001 and SOC 2 Type II. Customers include Australian Unity and Optus.

4. BraveGen

Best for: mid-sized and large organisations reporting across Australia and New Zealand.

BraveGen is based in Auckland with an office in Sydney, and builds carbon accounting and building optimisation software for Australia and New Zealand. Its ASRS module consolidates Scope 1, 2 and 3 data, applies more than 40,000 emission factors from libraries including NGERS and New Zealand's Ministry for the Environment, and generates disclosure reports aligned with ASRS. Every data change is tracked for the assurance review, and BraveGen states that its platform has supported hundreds of assurance-grade audits, including with Big 4 firms. Its consulting team runs Scope 3 workshops, board education and scenario analysis sessions. Customers include NAB, ASB Bank, Spark and SG Fleet.

5. Watershed

Best for: large enterprises with an established sustainability team and a broad Scope 3 programme.

Watershed is a Leader in the 2026 Verdantix Green Quadrant and the 2026 Forrester Wave for sustainability management software. It has a library of 2.3 million emission factors, drafts reports across frameworks with AI, and shows the lineage behind each number. It runs an Australian site, has published AASB S2 guidance and has run AASB S2 filing events. Canva is a customer.

6. Sweep

Best for: multi-entity groups that want carbon accounting inside a wider sustainability data platform.

Sweep, headquartered in Paris and London, is a Leader in the 2026 Verdantix and IDC reports. Carbon is one dataset inside its wider ESG platform, alongside supplier portals and a complete data trail. Sweep publishes AASB S2 preparation guides for Australian companies.

7. Persefoni

Best for: finance-led disclosure programmes and organisations that need financed emissions.

Persefoni calls its platform AI-native software for assurance-grade GHG reporting, and it is a Leader in the 2026 IDC MarketScape. Its analytics were built for private equity and asset managers, so it is one to look at if you are a superannuation fund or asset owner caught by Group 2.

8. IBM Envizi

Best for: distributed groups consolidating emissions data across many sites and business units.

Envizi is IBM's ESG data platform and a Leader in the 2026 Verdantix Green Quadrant. It pulls data from ERP systems, meters and utility bills, checks it, and keeps an audit trail an assurer can follow. Downer Group and GPT Group are Australian customers.

Four tests AASB S2 sets your software

Scope 1 and 2 go to the assurance provider in your first report, so meter and invoice data for the whole year has to be in the system from day one of that year. A Group 2 company with a June year end started that clock on 1 July 2026.

Assurance starts limited and reaches reasonable assurance over the whole report by your fourth year. Each step asks for more evidence behind the same numbers, so a method the assurer accepted in year one has to hold up under closer inspection later.

Scope 3 enters your second report. A base year, supplier data and a method your assurer will accept take most of a year to build, and for food, grocery and agricultural companies the bulk of Scope 3 comes from land.

Then there are the climate statements themselves: governance, strategy, risk management, and metrics and targets, drafted, reviewed and signed by your directors. Software that stops at a tonnage figure leaves that work with you.

Seven questions to ask any vendor

Here is a list of questions to ask your vendor during a demo:

1. Who assured your methodology, and when? Ask for the assurer's name and the date.
2. Can you trace one reported figure back to the raw data? Ask the vendor to do it live, on their own screen.
3. Which Australian emission factors do you use, and how often are they updated?
4. Does the platform draft the AASB S2 disclosures? Ask to see the output, and who gets to change it before sign-off.
5. Can it footprint a product when the supplier has sent you nothing? Most suppliers will send nothing this year.
6. What happens at the annual refresh? If the pipelines get rebuilt each year, the second report costs as much as the first.
7. Are specialists included, and who sits in the meeting with your assurance provider? If the answer is a support ticket, budget for a consultancy as well.

Related reading: Group 2 and 3: your AASB S2 deadline is closer than you think · Australia's climate disclosure rules: what you need to know · The 10 best carbon management platforms for enterprise supply chains (2026) · Climate reporting for IFRS S2 · Dyno Nobel case study

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