File your corporation tax and company accounts for £10 + VAT
One price, both filings. Submit your CT600 and iXBRL accounts straight to HMRC and Companies House. Sync directly from Xero or QuickBooks, or upload your own spreadsheet. No subscription. No annual licence.
Sign up freeNo card required. Only pay £10 + VAT when you submit.
A real CT600 computation in the app.
Built for directors and accountants alike
Whether you're filing for your own company or for clients, Tax Optimiser works the way you do.
Company directors
File your own corporation tax return and statutory accounts without needing an accountant. Our guided workflow handles the CT600 boxes, the iXBRL tagging, and the submission to HMRC and Companies House — £10 + VAT covers both filings for the year.
See how it works →
Accountants and bookkeepers
Buy credits in bulk and bring per-filing cost down to £3. File CT600s for as many clients as you like, sync directly from each client's Xero or QuickBooks, and submit to HMRC and Companies House from one place.
See credit pack pricing →From accounts to filed CT600 in three steps
Connect Xero or QuickBooks, or upload a spreadsheet
Link your accounting software in under two minutes using OAuth, or upload your own trial balance spreadsheet. We map the chart of accounts automatically — no manual re-keying.
Review, map and adjust
Map your trial balance to the CT600 computation with our guided workflow. Post adjustment journals that sync back to your accounting system. Built-in validation flags issues before you submit.
Submit CT600 + iXBRL and track deadlines
We generate iXBRL-tagged accounts and your CT600 and submit them directly to HMRC and Companies House from the app. Companies House deadline tracking is built in. You get confirmation receipts in minutes.
Long periods and part-filed years, handled
Periods longer than 12 months
If your period of account runs past 12 months, HMRC needs two CT600s: one for the first 12 months and one for the rest. We split the profits, capital allowances and tax between the two returns for you and file both from the same set of accounts. Every period costs the same, however long it is — two returns, one fee.
Read the long period guide →
Already filed your accounts? Just file the CT600
If your accounts are already at Companies House, filed by your accountant or another tool, you don't need to file them again. Mark the Companies House filing as not required, set the period to match the accounts you filed, and submit just the CT600 to HMRC.
Read the CT600-only guide →See exactly what you get
These are real screens from the app — the same ones our step-by-step user guide walks you through. No mock-ups, no surprises after you sign up.
The End of Year wizard on the dashboard.
Start with a wizard, not a blank form
The End of Year wizard walks you through company details, trial balance, accounts review and submission in one guided flow — you can't get lost. Your numbers come in however you keep them: straight from Xero or QuickBooks, an uploaded spreadsheet, or keyed in by category.
The tax maths is done for you
Add-backs, marginal relief, losses, the small profits rate — calculated automatically and shown in a computation you can actually read. Your corporation tax payable updates live at the top of the screen as you work, so there's never a surprise at the end.
Read the computation guide →
The generated computation, with marginal relief worked through.
Asset pools feeding the computation automatically.
Capital allowances without the spreadsheet
Record asset additions once and let the app handle the pools — main pool, special rate, cars, structures and buildings. Annual Investment Allowance is allocated for you and everything flows straight into the computation and the CT600.
Read the capital allowances guide →Guided submission to HMRC and Companies House
FRS 105 or FRS 102 1A accounts are built from the same trial balance and tagged as iXBRL automatically. Two short wizards validate, verify and review the documents, then send everything directly — your CT600 and computations to HMRC, your accounts to Companies House. Receipts arrive in minutes, and the deadline tracker updates itself.
Validation, verification, review, send — the whole submission wizard.
Exactly what the CT600 covers
Check your return is in scope before you sign up. Everything listed here is calculated, tagged and filed to HMRC from the app.
The main return
Trading profits, with disallowable expenses added back
Main rate, small profits rate and marginal relief, including associated companies
UK property income
Non-trade interest and other loan relationships
Investment income and other income
Chargeable gains, with indexation allowance
Management expenses
Charitable donations
Income tax suffered and double taxation relief
Quarterly instalment payment indicators
Repayment claims and bank details
Capital allowances
Annual Investment Allowance
Main pool and special rate pool
Cars
First-year allowances for zero-emission cars, zero-emission goods vehicles and EV charge points
Structures and buildings allowance
Balancing charges and allowances
Allowances on property and non-trade activities
Losses and reliefs
Trading losses brought forward
Trading losses carried back, including terminal loss relief
Property losses
Non-trade loan relationship deficits
Capital losses
Group relief claimed and surrendered
Periods and company types
Periods of account longer than 12 months, split into two returns for you
Short accounting periods
CT600 only, when your accounts are already filed at Companies House
Amended returns
Nil returns for dormant companies
Limited companies and community interest companies
Charities and CIOs
Clubs and unincorporated associations
Supplementary pages
CT600A — loans to participators (s455)
CT600B — controlled foreign companies and hybrid mismatches
CT600C — group and consortium relief
CT600D — insurance (Overseas Life Assurance Business declaration)
CT600E — charities and community amateur sports clubs
CT600F — tonnage tax
CT600H — cross-border royalties
Not sure about your return? Ask us →
What our customers say
I recently used Tax Optimiser for the first time to submit my accounts to Companies House and HMRC, and I’m thoroughly impressed. The platform is remarkably easy to manage, walking you through the entire process without any complex jargon. On top of that, their prices are extremely competitive. It saved me a ton of time and stress—I will definitely be using them again next year.
I had next to no confidence that Tax Optimiser could handle accounts submission and Corporation Tax. But I gave it a whirl… Both Companies House and HMRC have initially accepted the submissions… I previously filed on professional software and I paid about £1500. This is dirt cheap.
Excellent software. Very affordable if you're doing your own small company accounts. Links with Xero… Tax Optimiser has been a complete life saver for me.
Simple, honest pricing
One filing or a thousand — the more you buy, the less you pay. Working papers are included free with every filing.
Pay-as-you-go
per company, per year — covers both your statutory accounts and corporation tax submission. How pay as you go CT600 filing works
FRS 105 or FRS 102 1A accounts
Corporation tax (CT600) return
Direct Xero & QuickBooks sync
Automatic iXBRL tagging
Direct submission to Companies House and HMRC
Email support
For accountants and bookkeepers
One credit = one company, one year, both filings. All prices + VAT.
| Pack | Credits | Price | £ per credit |
|---|---|---|---|
| Pay-as-you-go | 1 | £10 | £10 |
| Starter | 25 | £200 | £8 |
| Practice | 100 | £600 | £6 |
| Growth | 250 | £1,250 | £5 |
| Scale | 500 | £2,000 | £4 |
| Enterprise Best value | 1,000 | £3,000 | £3 |
All prices exclude VAT. Credits do not expire.
Sign up to buy credits
This is the entire checkout. £10 + VAT when you submit — no subscription hiding behind it. Real screen, no mock-ups.
See every screen before you sign up
Our free user guide walks through the whole journey — from creating your first accounting period to the HMRC and Companies House receipts — using the same screenshots you've seen on this page. Read it online or download the PDF edition.
Frequently asked questions
Further reading
More from Tax Optimiser
File your CT600 for £10 + VAT. No subscription. No surprises.
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