Carbon accounting software calculates your company's greenhouse gas emissions from activity and spend data, organises them into scope 1, 2 and 3 under the GHG Protocol, and produces the reports customers, tenders and regulators ask for. For an SME the realistic choice is between about eight products, a free government template and a spreadsheet. The best one is the one that produces the document you actually have to deliver, at a price you can see before you sign. In our August 2026 check only one competitor, EcoHedge, published a price; Hedgehog publishes one too, and several vendors offer a free way in.
We make one of the tools in this guide. It appears with its price, its review count and its weaknesses, on the same terms as everything else.
What does carbon accounting software actually do?
It replaces three jobs you would otherwise do by hand.
Collecting data. Energy bills, fuel, travel, purchases and supplier figures are entered, uploaded or pulled in from other systems.
Converting data into emissions. Each line is multiplied by an emission factor, kilograms of CO2e per kWh, per litre, per kilometre or per euro spent. A platform carries a library of these factors and keeps them current.
Reporting. The result is organised by scope and category, compared with last year, and turned into an output: a GHG Protocol inventory, a carbon reduction plan for a UK tender, a CO2-Prestatieladder submission, or the emissions section of a sustainability report.
The value of software over a spreadsheet is not the multiplication. It is that year two is comparable with year one, that every number can be traced back to a source, and that several people can contribute without breaking the file.
What kinds of carbon accounting software are there?
Five kinds of product compete for the same search, and they solve different problems.
| Kind of tool | What it is good for | Typical price signal | Fits |
|---|---|---|---|
| Free calculator | A first estimate in an afternoon | Free | Curiosity, a first internal number |
| SME platform | A full organisational inventory, repeated every year | Free tier, then low four figures a year where published | Most companies of 10 to 500 people |
| Platform with adviser | Software plus a person who builds the first inventory with you | Quote only | First-time reporters without in-house knowledge |
| Enterprise suite | Multi-entity groups, audit workflows, wider ESG disclosure | Quote only, usually far higher | Large and listed companies |
| Product footprint (LCA) tool | Footprints of products, not organisations | Licence or project fee | Manufacturers answering product questions |
Most disappointment comes from buying the wrong kind, not the wrong brand. An enterprise suite is too much for a 40-person supplier, and a calculator is too little the moment a customer asks for a breakdown. If your question is about a product rather than your company, read LCA vs carbon footprint first.
How do you compare carbon accounting software?
Six questions separate the tools that look alike on a feature page.
- Does it produce the output you must deliver? Ask for the actual document: the PPN 006 carbon reduction plan, the ladder submission, the customer template. A dashboard is not a report.
- Can you see the price, including year two? Many vendors price on seats, entities and bundled advice, so ask what the second year costs and what extra users or locations add.
- Can you test it on your own data for free? A free tier or trial with one month of real energy and fuel data tells you more than any demo.
- How does it handle scope 3? Most SME footprints are dominated by purchased goods, transport and travel. Check whether the tool supports spend-based estimates first and supplier-specific data later. Our explainer on scope 1, 2 and 3 covers why.
- Can you trace a number back to its source? An auditor or customer will ask which factor turned an input into an entry.
- Who helps you, and is it included? Find out whether support is a person, a chatbot or a paid consultancy day.
For the method behind the numbers, see choosing the right carbon accounting method.
Which carbon accounting software do SMEs shortlist?
These are the products that come up most in SME comparisons, sorted on facts you can check rather than marketing claims.
| Vendor | Built for | Free way in | Published annual price | G2 rating |
|---|---|---|---|---|
| EcoHedge | UK SMEs | Yes, Lite tier | Yes, GBP 990 | Not listed |
| Hedgehog | EU and UK SMEs and mid-market | Yes, free edition | Yes, EUR 1,200 | 4.7 from 9 reviews |
| Seedling | UK SMEs, adviser included | Start for Free signup, no confirmed tier | No | 5.0 from 11 reviews |
| Persefoni | Enterprise, with a free tier | Yes | No | 4.8 from 11 reviews |
| Coolset | EU mid-market, ESG breadth | No | No | 4.7 from 18 reviews |
| Greenly | EU and UK mid-market | No | No | 4.7 from 27 reviews |
| Normative | EU and UK | Not stated | No | Not listed |
| Ecologi | UK small business | Not stated | No | 4.8 from 10 reviews |
Pricing, free tiers and ratings were read on 27 August 2026 from each vendor's pricing page, its G2 profile or our internal competitor census. Of eleven competitor pricing pages we attempted that day, three returned an error and were never read, and of the eight that loaded only EcoHedge carried a number. The second published price in the table is our own. SmartTrackers, the Dutch CO2-Prestatieladder specialist, was one of the three pages that errored that day; when we read its prices page on 3 October 2026 it listed its Start plan at EUR 1,545 a year excluding VAT. Treat every row as a starting point and check it again before you buy.
Two things stand out. Where vendors publish a price, a paid entry plan costs between GBP 990 and EUR 1,545 a year, and everything above that is negotiated. And review volume is thin across the SME end of the market: Greenly's 27 G2 reviews are a better evidence base than our 9. For a fuller cost breakdown, read carbon accounting software pricing compared.
Which software fits your situation?
The right shortlist depends more on what triggered the purchase than on the size of your company.
A Dutch tender. Public work in the Netherlands runs on the CO2-Prestatieladder and MKI. See best carbon accounting software for Dutch tenders.
An NHS or UK public contract. See best carbon accounting software for NHS suppliers.
A large customer collecting value chain data. See best carbon accounting software for CSRD value chain suppliers.
Your sector. We compare the options for construction, manufacturing, logistics, food and beverage, packaging and apparel.
You are already looking at one vendor. Our alternatives pages for Coolset, Ecochain and ClimatePartner, and our Hedgehog vs EcoHedge comparison, set out who else fits the same need.
Is a spreadsheet or a free calculator enough?
For a first year in a genuinely small business, often yes.
With one site, one energy supplier, a few vehicles and a purchase ledger you understand, a spreadsheet built on a published factor set gives a legitimate scope 1 and 2 figure. Three things break it: the second year, when a rebuilt calculation no longer compares with the first; the second customer, who wants the same data in a different template; and scope 3, where the number of lines outgrows what stays auditable. We weigh this up in is a free carbon calculator enough? and carbon accounting in Excel vs a platform.
What does Hedgehog do, and where does it fall short?
The Hedgehog Carbon Platform guides you through GHG Protocol setup, inventory building, data upload and reporting with an AI assistant, with human GHG experts reachable in the app. It carries more than 20,000 spend-based and activity-based factors plus your own supplier-specific data, handles several entities and sites, and reports to the GHG Protocol, PPN 006 and the CO2-Prestatieladder. The free edition covers a first footprint with five emission sources, one user and one entity, with no sales call. Pro starts at EUR 100 a month, EUR 1,200 a year on our G2 profile.
Our own customers name four weaknesses on our public G2 profile.
Loading data is manual. A small business reviewer said in August 2026 that it works well once the data is in, and that getting it in takes effort.
Few integrations. A mid-market reviewer asked for more in June 2026.
No forecasting. A small business reviewer noted its absence in August 2026 and was told it is on the development list.
Not a broad ESG suite. A mid-market reviewer rated us 3.5 out of 5 in June 2026 and found the platform less complete for wider ESG and CSRD reporting.
How should you run the decision?
Give it two weeks. Open free accounts with two vendors, load one real month of energy, fuel and travel data into each, and see which one copes with your actual files. Then ask each shortlisted vendor the same two questions in writing: what does year two cost, and what happens to last year's figures when emission factors are updated.
If you want to try it on your own data, you can start a free account without a sales call, or book a meeting if you would rather talk it through.
FAQ
What is the best carbon accounting software? There is no single best tool. For an SME the best choice produces the report you must deliver, shows its price including year two, and lets you test it on your own data first. Enterprise suites rank highly in search but are built for multi-entity groups.
Is there free carbon accounting software? Yes. Free calculators give a quick estimate, and several platforms, including Hedgehog, EcoHedge and Persefoni, offer a free tier or edition. A free tier usually covers one entity and a limited number of emission sources.
How much does carbon accounting software cost? Where vendors publish a price, paid SME plans start between GBP 990 and EUR 1,545 a year. Most vendors only quote on request, pricing on users, entities and included advice.
What is the difference between carbon accounting software and ESG software? Carbon accounting software measures and reports greenhouse gas emissions. ESG software covers a wider set of social and governance disclosures, often including emissions. We explain the split in ESG reporting software vs carbon accounting.
Sources: Hedgehog on G2, Coolset on G2, Greenly on G2, Seedling on G2, Persefoni on G2, EcoHedge pricing, vendor pricing pages and our internal competitor census, all read 27 August 2026. Hedgehog free edition and monthly price from hhc.earth/platform, read 3 October 2026.
