Help us improve OneSixth before launch
We're opening early access feature by feature — and across every platform we support. Put a real scheme through its paces on Xero, QBO, Sage or FreeAgent, shape the workflow, and tell us where it can be sharper. We'll invite you as each area opens up.
The problem
Specialist VAT schemes don't fit cloud accounting platforms
Xero won't calculate it
Xero, QuickBooks, Sage, and FreeAgent are excellent at standard VAT. None of them automate partial exemption, TOMS, or VAT margin schemes. Xero's own product team has acknowledged this on their public ideas board. The major platforms have decided the calculation belongs in the practitioner's hands — which means a spreadsheet.
The spreadsheet breaks the digital link
MTD for VAT requires an unbroken digital link from source records to submitted return. HMRC tolerates a spreadsheet workflow as long as the link is unbroken — but the moment a backdated invoice arrives, or a transaction is recategorised after submission, the spreadsheet is stale. The compliance failure isn't visible until HMRC asks.
The annual adjustment compounds errors
Partial exemption is provisional all year. At year-end you recalculate, post a single adjustment journal, and live with the consequences if transactions have moved. The adjustment is mathematically correct but loses the trail back to which transactions caused which movement. A year of errors compounded into one figure.
OneSixth was built to fix this — without replacing the ledger.
Built for accounting firms across the UK
Xero · QBO · Sage · FreeAgent
All four major UK platforms
HMRC-compliant
All current live guidance
Free to start
30-day trial, no card needed
Four steps to margin VAT compliance
Works the same way for every scheme — connect, choose, record, post.
Connect Your Ledger
Sign in with Xero, QuickBooks Online, Sage, or FreeAgent. Secure OAuth — we never see your password.
Select Your Scheme
Choose which VAT scheme applies to each organisation — motor trade, TOMS, second-hand goods, partial exemption, or more.
Record or Pull Data
Add stock records, classify transactions, or let us pull data from your accounting platform automatically.
Calculate & Post
Review the calculation, preview the journal, then post directly to your ledger with a full audit trail.
Everything you need for margin VAT
Multi-Platform, Multi-Org
Connect Xero, QuickBooks Online, Sage, and FreeAgent — all from a single dashboard. Switch between clients instantly, manage team access with role-based permissions, and keep every firm's data organised.
Margin VAT & Partial Exemption
Automatically calculate VAT due on the margin for every supported scheme — motor trade, second-hand goods, global accounting, horses, and TOMS — plus full Partial Exemption with provisional quarters and the annual adjustment. HMRC-compliant figures, no spreadsheets.
Journal Posting & Audit Pack
Review the calculated adjustments, preview the journal, then post directly to Xero, QBO, Sage, or FreeAgent in one click. Every action is captured in a comprehensive audit log with downloadable audit packs for HMRC.
Firms & Accountant Portfolios
Invite team members with admin, member, or read-only advisory roles. Accountants get a portfolio view across every client entity, with accountant-led billing built in.
Every margin scheme & partial exemption, one platform
Pick the scheme that applies to each organisation. All HMRC-compliant, all posting directly to Xero, QBO, Sage, or FreeAgent.
Second-Hand Goods
LiveAntiques, works of art, collectors' items, and general second-hand goods.
HMRC guidance →Global Accounting
LiveSimplified scheme for high-volume, low-value second-hand goods dealers.
HMRC guidance →Partial Exemption
LiveStandard Method with quarterly provisional recovery and the annual adjustment.
HMRC guidance →Houseboats & Caravans
Coming SoonMargin scheme for second-hand houseboats, caravans, and motor caravans.
Auctioneers
Coming SoonAuctioneers acting as agents or principals under the margin scheme.
Need help? We're here.
Whether you have a question about margin VAT, need technical help, or want to discuss your firm's needs — our UK-based team is ready to assist.
General enquiries: hello@onesixth.app · Sales: sales@onesixth.app · Billing: billing@onesixth.app