Most people start here
I need my tax return filed
One Self Assessment, drafted from your own documents and filed straight to HMRC. £29 a return, paid when you file — not before.
SA100 · 2025/26 · deadline 31 Jan 2027Live — Available now
The AI accountant for UK business. Self Assessment first.
Self Assessment is live today and HMRC-recognised: connect your bank, your accounts and HMRC's own data, review the draft, file with a receipt. Books, VAT, payroll and Corporation Tax run on the same numbers and are in open beta — try them alongside your return.
ac-co.ai is the AI back office for UK business — clean books, every UK tax, payroll and grounded legal AI, all running on one set of numbers. Self Assessment is the part that is out of beta — start there.
£29 a return — 50% off until 14 January 2027. No card to start · UK-only · HMRC-recognised.
BUILT FORSole tradersLandlordsInvestors & cryptoHigh earnersSide hustles
Live · click to watch
Three ways in. Pick yours.
Everything ac-co does sits behind one of these three doors — and each product says plainly whether it is live, in open beta, or still a waiting list. Nothing here is a promise about next year.
I run a business
Clean books underneath, and every UK filing drafted from them — VAT, MTD income tax, Corporation Tax, payroll, plus legal AI grounded in your own documents. All in open beta.
- BooksBeta — Open beta — join the waitlist, we open seats in batchesClean books, magically on autopilot.
- VATBeta — Open beta — join the waitlist, we open seats in batchesReconciled and filed every quarter.
- Income Tax (MTD)Beta — Open beta — join the waitlist, we open seats in batchesQuarterly updates drafted from your ledger.
- Corporation TaxBeta — Open beta — join the waitlist, we open seats in batchesCT600 + iXBRL, computed in one pass.
- PayrollBeta — Open beta — join the waitlist, we open seats in batchesGross to net, payslips and P60s.
- LegalBeta — Open beta — join the waitlist, we open seats in batchesLegal AI that cites its sources.
I run a practice
One client record for the whole firm — engagements, AML, bulk filing — and a front office that answers the phone. We are onboarding firms one at a time.
- Practice OSBeta — Open beta — join the waitlist, we open seats in batchesClients, engagements, AML and bulk filing.
- NexusBeta — Open beta — join the waitlist, we open seats in batchesCRM, shared inbox and calls in one front office.
- E-SignBeta — Open beta — join the waitlist, we open seats in batchesSend a document for signature, keep the audit trail.
- VaultBeta — Open beta — join the waitlist, we open seats in batchesYour documents, parsed and searchable.
- Tracker & TimesheetsBeta — Open beta — join the waitlist, we open seats in batchesProjects, tasks and billable time on one board.
Wired into
HMRC · recognisedCompanies HouseOpen BankingXeroQuickBooksMicrosoft WordChatGPT · Claude · CodexTHE COST OF DOING NOTHING
Three numbers HMRC will hold you to.
£100
One day late is still late
HMRC's late-filing penalty is automatic and lands even when you owe no tax at all. Three months late and it becomes £10 a day on top, up to a further £900.
Source: HMRC — Self Assessment penalties (opens in a new tab)£50,000
Making Tax Digital starts 6 April 2026
Qualifying income over £50,000 in 2024-25 means quarterly digital updates from April 2026 — then £30,000 from April 2027, and £20,000 from April 2028. Spreadsheets stop being enough.
Source: HMRC — Check if you're eligible for MTD for Income Tax (opens in a new tab)£90,000
The VAT line you can cross by accident
Taxable turnover over £90,000 in any rolling twelve months means registering for VAT — and filing every quarter, digitally, from then on. The clock is the last twelve months, not the tax year.
Source: HMRC — Register for VAT: when to register (opens in a new tab)HOW IT WORKS
From connected to filed, in four moves.
No sign-up — try it right here
See your Self Assessment bill in ten seconds.
Type in what you earned. The same engine that fills the return works out the income tax and the National Insurance — it runs in your browser, and nothing you type leaves it.
An estimate from the figures you type, for the tax year you pick — not tax advice, and not a filing. All the calculators →
TRUST
We file in your name, so we hold ourselves to the highest bar.
ac-co is HMRC-recognised software submitting through the official API. Connections to your bank and books are read-only. Every figure traces to a source, and every receipt is stored for six years.
HMRC
recognised software
Companies House
joint filing
Open Banking
read-only access
UK GDPR
data resident in London
Human-in-loop
you approve every submission
Records kept
6 years, automatic
WHAT YOU GET
Everything the platform files, keeps and tells you.
Files for you
Sent to HMRC and Companies House, each with a receipt.
- SA100Your Self Assessment, with an HMRC receipt.
- VAT returnThe nine MTD boxes, filed every quarter.
- CT600 with iXBRL accountsFiled to HMRC and Companies House.
- Confirmation statement
- RTI for payrollFPS and EPS, each pay run.
Keeps for you
A ledger and a source document behind every figure.
- A ledger behind every box
- The source document for every figure
Tells you
What is due, and what it will cost, before it lands.
- What is due, and when
- What your next bill will be
One price per entity. Every mandatory filing inside.
Self Assessment is a flat fee per return — draft it for free and pay only when you file. Everything else is one plan for your entity, not a feature tier.
Sole trader
Open beta · SA100 live£14
or £140/yr, paid annually
Join the waitlistIncluded filings
- ✓MTD ITSA quarterly updates + final declaration
- ✓SA100 Complete
Included modules
- ✓1 front office seat
- ✓1,000 AI credits / mo
Instead of: Xero Simple £7 (no SA100) · Coconut Full £13.33 · FreeAgent £19
Landlord
Open beta · SA100 live£14
or £140/yr, paid annually
Join the waitlistIncluded filings
- ✓MTD ITSA quarterly updates + final declaration
- ✓SA100 Complete
- ✓SA105
- ✓joint ownership
Included modules
- ✓3 properties included
- ✓1 front office seat
- ✓1,000 AI credits / mo
Instead of: FreeAgent Landlord £10 · Hammock £8–31.50
Limited company
Open beta · SA100 live£39
or £390/yr, paid annually
Join the waitlistIncluded filings
- ✓VAT
- ✓CT600 + iXBRL
- ✓confirmation statement
- ✓RTI payroll for 2 directors
- ✓1 SA100
Included modules
- ✓2 employees on payroll included
- ✓1 front office seat
- ✓3,000 AI credits / mo
Instead of: FreeAgent £33 · Xero Grow £39 + £10 CT + payroll · QuickBooks £38 + £8 · Sage £43
Practice
Open beta£40
or £400/yr, paid annually
Join the waitlistIncluded filings
- ✓Everything above, for every client of the firm
Included modules
- ✓500 AI credits / mo
Instead of: Sage £3/client · Coconut £5.50/client · Xero Cashbook £7–11/client · Dext £9–18/client
SWITCHING
What moves across, and what it costs.
From Xero
What moves
- ✓Bank feed history
- ✓Chart of accounts
- ✓Contacts
- ✓Open invoices
Cost — FreeEffort — Same day for the ledger
From QuickBooks
What moves
- ✓Bank feed history
- ✓Chart of accounts
- ✓Contacts
Cost — FreeEffort — Same day for the ledger
From Spreadsheet
What moves
- ✓Nothing to import
Cost — FreeEffort — We do it with you
OBJECTIONS
Before you buy.
Is this really cheaper than Xero plus add-ons?
Xero's own Grow plan is £39/mo (xero.com/uk/pricing-plans, read 2026-09-13) and still doesn't file your Corporation Tax or Self Assessment — those are separate add-ons or a separate accountant. ac-co's plans carry the mandatory filings inside the price.
What if my situation doesn't fit a plan?
Plans follow your entity — sole trader, landlord, limited company — not a feature tier. If you genuinely don't fit one of the four, /pricing shows every module and band so you can see exactly what changes the price.
Can my accountant work in it?
Yes — invite them into your workspace to review a draft before anything is filed, whether or not they use ac-co day to day.
What if a filing is wrong?
Every figure traces to a source document or bank transaction, and a human taps to file — nothing submits itself unreviewed.
What happens to my data if I leave?
You export it, and if you're a client of a firm on our Practice plan, your entity moves with you to a retail plan rather than being locked to the firm.
The AI accountant for UK business. Self Assessment first.
Self Assessment is live today and HMRC-recognised: connect your bank, your accounts and HMRC's own data, review the draft, file with a receipt. Books, VAT, payroll and Corporation Tax run on the same numbers and are in open beta — try them alongside your return.
£29 a return — 50% off until 14 January 2027. No card to start · UK-only · HMRC-recognised.