The 5 best carbon accounting software platforms 2026
Your guide to choosing the carbon accounting vendor that suits your business, comparing platforms on accuracy, compliance support, supplier engagement, and expert guidance.
The best carbon accounting software helps businesses do more than meet compliance requirements or build stakeholder credibility. It enables real emissions reductions and delivers strategic value across the organization.
Today’s leading businesses use carbon accounting platforms to proactively plan future emissions reductions, embed carbon insights into strategic decisions, and maintain robust, auditable data for investors, auditors, and customers. Below, we assess the five leading platforms to help you identify which is right for your business.
The best carbon accounting software assessed
Normative
Best for: Enterprises seeking audit-ready carbon data, scope 3 accuracy, and certified climate strategy expertise.
Overview: With customers across a range of industries and offices in London, Stockholm and Copenhagen, Normative is the original carbon accounting platform. Its carbon management platform and climate experts empower organizations to turn carbon data into smart sustainability actions.
Positives:
- System of record for carbon data: The platform combines automated data ingestion with AI-driven categorization and built-in quality control to reduce manual effort and improve consistency across reporting cycles. Scientifically validated calculations across Scopes 1, 2, and 3 provide a reliable, audit-ready foundation for both compliance and decision-making, thanks to 21 scientific databases, thousands of emission factors and taxonomy that’s refreshed every 6 months.
- Normative’s software has been verified by TÜV SÜD following an evaluation based on ISO 25051 and the GHG Protocol.
- Value chain expertise: To strengthen value chain accuracy, Normative enables access to verified supplier data through the Carbon Network, helping organizations improve Scope 3 coverage and engage suppliers more effectively.
- Expertise of a climate consultancy: Normative’s robust data foundation is paired with expert-led guidance from GHGP certified climate strategists, supporting customers as they navigate CSRD, SBTi, and evolving regulatory and voluntary standards.
- The Climate Strategy team has a 100% record for both audit success and SBTi approval and is now complemented by Normative’s AI Assistant. While the latter provides on-demand answers to help sustainability professionals better understand their own carbon data, Normative’s climate experts are on hand to dive deeper and provide advice on how to improve and next steps based on the data.
- As the earliest carbon accounting vendor on the market, Normative remains rooted in science with representation in GHG Scope 3 and ISO working groups.
- Together, Normative’s platform and expertise help teams simplify reporting, understand where to act, and drive measurable emissions reductions with confidence.
Notable customers: SEB, Vodafone, Hitachi
Sweep
Best for: Data-driven teams needing automation, AI-powered insights, and collaborative carbon management.
Overview: Founded in 2020 in France, Sweep also has offices in London and Denver, Colorado.
Positives:
- Sweep is a data platform that empowers users with automation, connectivity, and collaboration with innovative features like AI and scenario modelling.
- The company is a member of the World Bank’s Carbon Pricing Leadership Coalition.
- Sweep also partners with the likes of Capgemini, CDP and KPMG.
Notable customers: L’Oreal, SSE, Lacoste.
Watershed
Best for: Organizations prioritizing scenario modelling, ease of use, and streamlined one-click reporting.
Overview: Founded in 2019, Watershed has offices across the US and in London.
Positives:
- Scenario-based modelling: customers can model scenarios based on the insights they gain from carbon accounting.
- Ease of use: customers can benefit from data automation workflows and features like one-click reporting.
- CDP has partnered with Watershed to handle its own emissions reporting.
Notable customers: Walmart, Blackrock, Spotify
Greenly
Best for: SMBs and mid-market businesses in Europe seeking broad ESG coverage beyond carbon.
Overview: Founded in Paris in 2019, Greenly is a prominent vendor across Europe, especially with SMBs and businesses in the mid-market in the region.
Positives:
- Greenly provides a breadth of coverage across the spectrum of ESG, including GHG Assessment, Life Cycle Analysis and ESG Management.
- It offers a tailored approach for customers, depending on industry.
- The company’s EcoPilot AI is designed to give customers on-demand climate expertise and manage repetitive tasks.
Notable customers: Huawei, HSBC, Ubisoft
Persefoni
Best for: Financial services firms and organizations requiring finance-specific portfolio analytics and Scope 3 supplier engagement.
Overview: Having been founded in 2020, Persefoni is headquartered in the US with other offices in the UK, Singapore, Japan, Canada and Germany.
Positives:
- Persefoni specializes in delivering finance-specific features such as a portfolio analytics dashboard for Private Equity and Venture Capital firms, which includes emission Intensity and Asset Class features.
- Supply chain engagement: its supplier portal allows enterprises to gather real Scope 3 data from free supplier accounts.
- Persefoni AI is embedded into the platform and available for every plan to identify statistical anomalies and provide support for technical carbon accounting queries.
Notable customers: Xerox, Snowflake, Burlington
Why choosing the right carbon accounting software matters
Sustainability is now at the centre of our working lives. This is driven by all major stakeholders, whether it is the businesses you work with asking for reporting on your carbon emissions, investors looking to mitigate risk, or auditors and regulators assessing a business’ disclosures to mandatory frameworks like CSRD or voluntary frameworks like SBTi and CDP. There’s a common thread: all will be looking for granular carbon data.
With these demands comes great opportunities. The businesses that find the best carbon accounting software for their needs will be well placed to get a strategic advantage in three key areas:
Make money
- Tender eligibility: 90% of the FTSE 100 include ESG in tenders. Businesses that can prove they have a comprehensive grasp of their carbon emissions can make themselves more attractive to potential customers. In some cases this is a mandatory requirement, like the UK’s Procurement Policy Note (PPN) 06/21 which requires suppliers to publish and maintain a Carbon Reduction Plan in order to be eligible to bid for central government contracts worth in excess of £5 million.
- Increased revenue generation: 66% of C-suite execs state that high-priority sustainability efforts have had a positive impact on revenue generation.
Save money
Mitigate risk
- Cost of climate risks: $162 billion in financial losses could be incurred from supply chain climate risks, compared to the $56 billion that’s needed to mitigate them.
- Risk of unintentional greenwashing: 72% lower carbon calculations were delivered by Normative in an engagement with a higher education organization, compared with the calculations delivered by the industry-accepted HESCET tool. This is a significant risk if an organization is using inflated data to set targets and measure against progress.
Beyond making real progress against emission reductions and meeting compliance requirements, the wider business opportunities that stem from a smart use of carbon emissions data are significant. This makes the selection of a carbon accounting software vendor a critical decision. So, what are the key considerations you need to bear in mind when taking this step?
What questions should you ask when choosing carbon accounting software for your business?
Is the platform aligned with the Greenhouse Gas Protocol?
You need to have confidence that the vendor will be delivering carbon calculations that you can trust when sharing with customers, investors or auditors. Make sure you look into this and question whether items like scopes and categories are clearly mapped.
How does the platform ensure carbon accounting calculations are accurate?
Specifically here you should ask how frequently the vendor updates emission factors, how many are available and enquire about the depth of its taxonomy. All of these are clear indicators of how reliable the carbon calculations will be, as will the QA process that will be in place when dealing with your business’ data.
What carbon accounting data types are supported?
Every organization is at a different stage of carbon accounting maturity. This makes the conversation about the types of carbon accounting data that are supported really important. You need to know whether the vendor supports spend-based, activity-based, supplier- and/or product-specific data, to understand whether they will be a good fit for your requirements.
Is there clear documentation of the vendor’s methodology?
Having the vendor’s methodology documented is essential. You will need to explain carbon calculations to key stakeholders internally and externally, so you need to be clear on how these calculations are being made in order to communicate the data clearly and reliably when it really matters.
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Does the platform allow you to connect directly with suppliers?
Tackling scope 3 emissions is one of the biggest challenges for organizations taking on carbon accounting, due to the complexity and size of what are often complex, international supply chains. Scope 3 emissions form the majority of emissions for many companies, so the more you are able to get data directly from your suppliers, the more accurate your carbon calculations are going to be, and the better informed your strategic decisions will be to deal with emissions hotspots.
Does the platform support reduction planning?
If you’re ready to focus on implementing or building on existing emission reduction plans, you need a supplier that can support you through its carbon accounting software and expert climate advisors. Even if you’re not at this stage today, and just want to get started with building your carbon inventory, this is still the time to choose the best carbon accounting software that can grow with you when you are ready to focus on a reduction strategy.
How is auditability supported?
It’s important to establish the tangible features of the product that will help your business pass the scrutiny of an audit. As well as establishing the company’s prior audit record for customers, you should ask whether the software offers features such as emission factor traceability and calculation logs.
Is the software accompanied by access to certified climate experts?
Even the best carbon accounting software can’t guarantee your business success in its sustainability journey without some help. GHGP-certified climate specialists are crucial to not only help you with the essentials of building your carbon inventory, but also helping you navigate evolving regulation, SBTi submissions and guiding you through how to use the carbon data at your fingertips to the benefit of your business.
Does the vendor support submissions to frameworks such as the SBTi?
Making these submissions can be a time-consuming process, not to mention challenging if you haven’t done it before. If this is on your radar, check with the vendor what their experience and success rate is when it comes to SBTi submissions to ensure you handle the process successfully for your business.
Ready to take your next step?
Speak with one of Normative’s climate experts to share your requirements and uncover how the combination of our carbon accounting platform and GHGP-certified climate specialists can make a difference.
FAQs
Carbon accounting software enables organizations to calculate, manage, and report greenhouse gas emissions across Scopes 1, 2, and 3. Beyond calculation, today’s leading platforms help businesses proactively plan future emissions reductions, embed carbon insights into strategic decision-making, and maintain robust, auditable data to ensure credibility with stakeholders.
The best carbon accounting software depends on your organization’s size, industry, and reporting requirements. Normative is the original platform and suits enterprises requiring scientifically validated data and expert climate strategy support. Watershed and Sweep suit organizations prioritizing automation and scenario modelling. Greenly is well-suited to SMBs and European mid-market businesses seeking broad ESG coverage, while Persefoni specializes in financial services and portfolio analytics.
Choosing the best carbon accounting software for your business will come down to your specific criteria. But it is always important to ask about alignment with the Greenhouse Gas Protocol, how often emissions factors and taxonomy are updated, and whether the vendor’s methodology is clearly documented. These questions reveal how reliable and scientifically sound the platform’s calculations are, the non-negotiables of accuracy and scientific integrity.
AI can significantly reduce manual effort by automating data ingestion and categorization. For example, Normative uses AI-driven categorization and built-in quality control to improve consistency across reporting cycles, while its AI Assistant provides on-demand answers to help sustainability professionals understand their carbon data better. However, AI must be supported by clear QA processes and complemented by climate strategy experts who can provide strategic guidance and deeper analysis of what the data means for your business.
Whether carbon reporting is mandatory depends on a number of factors, including location, number of employees, and net turnover. For example, the EU’s CSRD requires extensive sustainability disclosures from qualifying companies. Carbon reporting can also be a competitive advantage, as in the UK, suppliers must publish a Carbon Reduction Plan to be eligible for central government contracts worth over £5 million under PPN 06/21. Voluntary frameworks like SBTi and CDP are also widely adopted, so choosing the right carbon accounting software is pivotal to helping businesses meet both mandatory and voluntary requirements.
Scope 3 emissions are the most complex to calculate due to the size and international nature of most supply chains, and they represent the majority of emissions for many organizations. Look for platforms that support direct supplier data collection, spend-based and activity-based data types, and maintain a large, frequently updated library of emission factors. Supplier portals, such as Normative’s Carbon Network, enable organizations to gather verified, real-world supplier data directly.
Accuracy depends on the quality and frequency of emissions factor updates, the depth of taxonomy, and the QA processes in place. Normative, for example, draws on 21 scientific databases, thousands of emission factors, and taxonomy refreshed every six months, and its methodology has been verified by TÜV SÜD based on ISO 25051 and the GHG Protocol.
Ask the vendor about their customers’ audit track record and look for specific platform features that support auditability, such as emission factor traceability and calculation logs. Normative’s Climate Strategy team, for example, has a 100% record for audit success.
Yes. When evaluating vendors, ask specifically about their experience with SBTi submissions and their approval rate. It’s crucial to not only ask how software supports SBTi submissions, but whether you will get dedicated support from a climate expert as well to help you navigate the process.
