Built for UK accountants. Uses DEFRA factors. SECR ready.
Your accounting ledger is already your carbon record
Stone connects to your cloud accounting ledger and turns every transaction into a carbon estimate automatically, then keeps it current as new transactions come in. It shows what those emissions cost, what cutting them saves, and how different futures hit your clients' numbers.
Connects to Xero today. QuickBooks and Sage on the roadmap.
Why Stone is different
Other carbon tools give you a number. Stone tells you what it means.
Connecting to the accounting software is the easy part, several tools do it. What none of them do is link those emissions back to the financial decisions that caused them, and show what changing those decisions costs or saves. That is Stone.
Starts from your full transaction history
Before you answer a single question, every fuel charge, delivery and utility bill already has an emission estimate against it. You are checking real numbers, not filling in a blank form from memory.
It speaks money, not just carbon
Stone shows what the emissions cost in pounds, the return on switching to electric vans, and how a future carbon price would hit profit. (Stone 2.0, 2027.)
It fills in the detail for you
For repeat costs like fuel and energy, Stone works out the physical amounts from the prices you paid, so nobody keys them in by hand. Every figure is checkable and shows how reliable it is. (Stone 2.0, 2027.)
Built on UK government DEFRA 2025/26 conversion factors and the GHG Protocol. Produces UK SECR reports today, and UK SRS (IFRS S1 and S2) disclosures as those standards arrive.
How it works
Automatic from the first sync. Audit-ready when you need it
The carbon estimate builds itself the moment Xero connects. These steps take it from a fast first estimate to a number you can sign off, and Stone keeps it current as the ledger changes.
Connect
Connect Xero in one click. Your whole ledger syncs in, every transaction and supplier, and keeps syncing.
Classify
Stone sorts each transaction into a Scope 1, 2 or 3 category and learns your choices, so it gets faster on every client over time.
Add detail
Add real-world figures (litres of fuel, kWh of energy) to the few transactions that need them for a sign-off-grade number. Stone does this for you from 2027.
See the money
See what the emissions cost, how a carbon price would hit profit, and what cutting them saves, straight from the financial data. (Stone 2.0, 2027.)
Report
Produce a UK SECR report today, with UK SRS and lender packs as those standards land. Every number traces back to the transaction behind it, year on year.
Ready to build ahead of the mandate?
UK SRS landed in February 2026 and larger customers are already asking your clients for emissions data. Start now and each client builds a clean, continuous history you cannot recreate later.