The honest answer for a straightforward limited company in 2026: £120 to £950 for a CT600 prepared and filed by an accountant, or £80 to £195 + VAT with Easy Digital Filing’s self-file software. Cheaper self-file products exist at around £59, but they do not state a VAT basis, so they are not comparable on the same footing. Most straightforward accountant-prepared cases land in the £299 to £575 band.
The spread is wide because “CT600 filing” means different things to different providers. Some quote for the tax return alone. Some include the year-end accounts. Some include the Companies House submission and some charge extra for it. Comparing headline prices without checking what sits underneath them is how directors end up paying twice.
One thing changed this year that affects everyone: HMRC’s free filing service closed on 31 March 2026. There is no longer a no-cost DIY route.
What CT600 filing actually costs in 2026
Accountant-prepared, one-off fixed fee
| Provider | Price | What’s included |
|---|---|---|
| Mazuma — CT600 only | £120 inc VAT | Corporation tax return only |
| Taxfix — dormant company | £89 + VAT | Dormant accounts and filing |
| Taxfix — non-VAT registered | £329 + VAT | Year-end accounts to Companies House and CT600 to HMRC |
| Taxfix — VAT registered, under £200k turnover | £419 + VAT | As above |
| Filing Accounts — micro and small | £350 | Accounts filing |
| SmartFiling — micro-entity | from £299 (no VAT added) | FRS 105 accounts, CT600, iXBRL tagging, both submissions |
| Mazuma — Trial Balance Package | £575 inc VAT | Accounts and CT600 from a trial balance |
| Mazuma — Paperwork Package | £950 inc VAT | As above, from unsorted records |
Self-file software
| Provider | Price | Notes |
|---|---|---|
| TinyTax — dormant | £20/year | |
| Taxpipe | £59 per return | CT600, computation and micro-entity accounts. Does not file with Companies House |
| TinyTax — one trading company | £59/year | Covers both HMRC and Companies House |
| Easy Digital Filing — CT600 only | £80 + VAT | No iXBRL accounts |
| Easy Digital Filing — micro | £119 + VAT | Includes micro iXBRL accounts; +£20 + VAT for Companies House |
| Easy Digital Filing — small | £195 + VAT | Includes small company iXBRL accounts |
Monthly subscription accountants
| Provider | Monthly | Annual equivalent |
|---|---|---|
| The Accountancy Partnership | from £39.50 + VAT | £474 + VAT |
| Mazuma | from £38 + VAT | £456 + VAT |
| Osome (Operate) | from £71 + VAT | £850 + VAT |
| Gorilla Accounting | £125 + VAT flat | £1,500 + VAT |
Traditional high-street firms
Traditional practices almost never publish prices. From the quotes directors report, £500 to £1,500 + VAT for accounts and CT600 together is the usual range, rising to £1,500–£3,500 for anything complex. Treat that as an estimate rather than a quoted figure — there is no published fee survey behind it.
Some online providers quote figures like “£1,000 + VAT at a high-street accountant” in their marketing. That is a competitor’s claim, not independent data.
The change that reshaped DIY filing this year
Until March 2026, HMRC ran a free joint filing service — commonly called CATO — that let small companies file accounts and a CT600 at no cost. It closed on 31 March 2026.
From 1 April 2026, companies must use commercial software to file a Company Tax Return with HMRC. Paper CT600s are only accepted with a reasonable excuse, or if you are filing in Welsh.
This matters for two reasons. The genuinely free DIY option is gone, so the real DIY floor is now around £59–£119 + VAT for software. And a lot of published guidance still references the free service, which will send you to a dead end.
Companies House is a separate story. Filing your annual accounts with Companies House is still free, on every route, and web filing still works. Software-only filing there begins in April 2028, not 2027 — the date was formally deferred on 9 June 2026.
What drives your quote up
Every online accountant runs some version of the same pricing engine. These are the levers.
Turnover. The most common banding factor. The Accountancy Partnership uses twelve turnover bands from £0–£20,000 up to £1,000,000+. Osome upgrades you automatically at £350,000 and invoices the difference retrospectively.
VAT registration. The cleanest single data point in the market: Taxfix charges £329 + VAT for a non-VAT-registered company and £419 + VAT for a VAT-registered one, with everything else held constant. That is a 27% increase purely for being VAT registered.
Transaction volume. Crunch bands on average monthly transactions — 0–10, 10–25, 25–50, 50–100, 100–200, 200+. If your bookkeeping is included in the fee, this is often the biggest driver.
Number of directors. Each director’s personal Self Assessment is usually charged separately. Typical add-ons run £10 + VAT per month per director, or £99–£250 as a one-off.
Structural complexity. Crunch explicitly prices up for multi-currency bank accounts, alphabet share structures, corporate shareholders, share values under £0.01, property ownership and e-commerce operations.
Backlog. The single largest cost multiplier. Osome charges £850 a year for historical annual filing and bookkeeping; Sleek charges £750 per financial year for backdated bookkeeping up to 100 transactions. If you are two years behind, the catch-up work will cost more than the current year.
Late filing. Not a fee as such, but it compounds. For returns with a filing date on or after 1 April 2026, HMRC’s penalty is £200 at one day late, another £200 at three months, then 10% of unpaid tax at six months and again at twelve. File late three years running and the flat penalties become £1,000 each.
What a fair quote should include
Ask any provider to confirm these in writing before you commit.
- CT600 preparation and submission to HMRC — the core deliverable
- Corporation tax computation — the working that supports the return
- iXBRL tagging — mandatory for HMRC; some software prices it separately
- Companies House submission — genuinely separate work; Taxpipe does not do it at all, Easy Digital Filing charges £20 + VAT extra
- Capital allowances review — claiming what you are entitled to on equipment, vehicles and fixtures
- Handling HMRC queries — whether follow-up correspondence is included or billed
- Amendments — what happens if the return needs correcting after submission
The two that most commonly turn into surprise invoices are Companies House submission and HMRC correspondence.
The VAT trap in price comparisons
Almost every UK provider quotes excluding VAT. The Accountancy Partnership, Gorilla, Taxfix, Osome, Sleek, 1st Formations, Easy Digital Filing, Crunch, Xero, FreeAgent and QuickBooks all state prices ex-VAT.
Mazuma is the one to read carefully, because it uses both conventions. Its monthly subscriptions are quoted plus VAT, like everyone else in that list. Its one-off packages — the £120, £575 and £950 figures in the tables above — are quoted inclusive of VAT. Same firm, two pricing pages, two bases.
Several providers — Taxpipe, TinyTax and Filing Accounts among them — give no VAT indication at all on their pricing pages.
At 20%, this is not a rounding difference. A “£350” quote and a “£350 + VAT” quote are £70 apart. And if your company is VAT registered, you reclaim the VAT anyway, which makes the ex-VAT figure the one that matters to you — but only if you know which you are looking at.
Is DIY worth it?
Run the arithmetic properly.
DIY cost: filing software at £80–£195 + VAT with Easy Digital Filing (or around £59 with Taxpipe or TinyTax, neither of which states a VAT basis), plus accounting software if you need it. Xero starts at £7 a month excluding VAT on its Simple plan, FreeAgent at £33 a month for a limited company — though FreeAgent is free for NatWest, RBS, Ulster Bank and Mettle business account holders, which changes the sum considerably.
Where DIY works: dormant companies, single-director companies with a handful of transactions, and directors who genuinely understand capital allowances and disallowable expenses. A £20-a-year dormant filing is hard to argue with.
Where it usually doesn’t: the moment there is a capital allowances judgement, a director’s loan account, mixed personal and business expenditure, or an R&D claim. One SmartFiling client’s previous accountant had missed capital allowances worth £2,200 — considerably more than the fee for having someone competent look at it.
A note on comparing the two columns fairly: the DIY figures above are quoted excluding VAT, and if your company is VAT registered you reclaim it. Several of the accountant prices in this article are quoted inclusive. Compare like with like before concluding one is cheaper.
There is also a professional indemnity point. If you file it yourself and get it wrong, the liability is entirely yours. An ICAEW-regulated firm carries PII insurance and is accountable to a regulator.
The pragmatic split: if your affairs are genuinely simple and you are comfortable with the technical rules, DIY software at £59–£119 + VAT is good value. If you are guessing at any part of it, the £299–£575 for a prepared return usually pays for itself in one claimed allowance.
Frequently asked questions
Can I still file a CT600 for free?
No. HMRC’s free filing service closed on 31 March 2026. Commercial software is now required for filing with HMRC. Filing accounts with Companies House remains free.
Why do some CT600 quotes look so much cheaper?
Usually because they exclude the year-end accounts, the Companies House submission, or both. A £120 CT600-only fee assumes your accounts already exist. Check what the price covers before comparing.
Does a dormant company need a CT600?
Only if HMRC has issued a notice to deliver a return. If you have properly notified HMRC of dormancy they will usually stop issuing them. Dormant filing services run £20–£100.
Is a monthly subscription better than a one-off fee?
It depends on what else you need. Subscriptions bundle bookkeeping, VAT returns, payroll and software, and typically run £456–£1,644 + VAT a year. If you only need accounts and a CT600 once a year, a one-off fixed fee in the £299–£575 range is usually cheaper. Check whether each figure includes VAT before comparing.
What if I’m behind on previous years?
Expect to pay per outstanding year, often at a premium. Late filing penalties are already accruing at both HMRC and Companies House, so the cost of waiting exceeds the cost of dealing with it.
What SmartFiling charges
SmartFiling files micro-entity accounts and the CT600 together from a fixed £299 — FRS 105 accounts, corporation tax return, iXBRL tagging, and submission to both Companies House and HMRC, with nothing charged separately. That bundle turns around in seven working days.
Standalone CT600 filing is available on a fixed fee where your accounts are prepared elsewhere. Capital allowances and R&D relief are reviewed as part of the work, not billed as extras. Standalone CT600 turnaround is three weeks from receiving complete records, or one week for an additional £150.
Every return is reviewed and signed off by an ICAEW Chartered Accountant. SmartFiling is the trading name of Ballards Newman (Finchley) Limited, an ICAEW-regulated London practice with over twenty years of UK tax experience.
