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Corporation Tax Return Accountant
Your company's Corporation Tax calculated, minimised and filed with HMRC, for a fixed fee
We prepare your company accounts and Corporation Tax return (CT600), claim every allowance and relief, file on time with HMRC and Companies House, and tell you exactly what to pay and when.
- CT600 filed on time
- Reliefs and allowances claimed
- Payment date confirmed
- Fixed fee, agreed first
Get your Corporation Tax fixed fee
Free, no obligation. We usually reply the same working day.
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How much will your Corporation Tax accountant cost?
Answer three quick questions about your company. Your fixed monthly fee updates instantly.
Your company
Includes your accounts, CT600, director payroll and the director's Self Assessment.
In short
What is a Corporation Tax return?
A Corporation Tax return, form CT600, reports a UK limited company's taxable profits to HMRC for each accounting period. It is filed with the company accounts within 12 months of the year end, but the tax itself is due earlier, 9 months and 1 day after the year end. Corporation Tax is charged at 19% on profits up to £50,000 and 25% above £250,000, with marginal relief in between.
- Small profits rate19% up to £50,000
- Main rate25% above £250,000
- Tax due9 months and 1 day after year end
- CT600 due12 months after year end
Who needs to file a Corporation Tax return?
You must file a Corporation Tax return if HMRC sends you a notice to deliver one. In practice, that includes:
- Every UK limited company that trades or makes a profit
- Companies with a loss, so the loss can be carried forward
- Clubs, associations and co-operatives with taxable income
- Overseas companies with a UK branch or permanent establishment
- Newly incorporated companies, from their first accounting period
- Dormant companies sent a notice, unless HMRC agrees they're dormant
New companies must register for Corporation Tax within 3 months of starting to trade.
Corporation Tax deadlines for your company
Your deadlines depend on your company's year end. Choose yours to see your exact dates.
- YE31 March 2026Your company year end
- ACC31 December 2026Accounts filed at Companies House
- PAY1 January 2027Corporation Tax payment due
- CT31 March 2027Corporation Tax return (CT600) due
Large companies with profits over £1.5 million pay Corporation Tax in quarterly instalments instead.
What's included in our Corporation Tax return service
Everything your company needs to stay compliant, for one fixed fee.
- Statutory year-end accounts
- Corporation Tax computation
- CT600 filed online with HMRC
- Accounts filed at Companies House
- Capital allowances, including the Annual Investment Allowance
- Research and development relief, where eligible
- Losses carried forward or back
- Associated company checks for the profit limits
- Director's loan account review
- Your payment amount and date in writing
- Answering HMRC letters about your return
- Unlimited questions by phone, email and video
How we prepare your Corporation Tax return
Four simple steps, all online.
Get your fixed fee
Tell us about your company and we confirm your price in writing.
Share your records
Connect your accounting software or send your bank statements and invoices securely.
We prepare your Corporation Tax return
We prepare your accounts and CT600, then send both to you to approve.
We file your Corporation Tax return
We file with HMRC and Companies House and confirm what to pay and when.
Legal ways to reduce your Corporation Tax
We check every relief your company is entitled to, so you never pay more than you should.
Corporation Tax allowances
- Annual Investment Allowance up to £1 million
- Full expensing for new main-rate equipment
- Writing down allowances on cars and other assets
Corporation Tax reliefs
- Research and development relief
- Trading losses carried forward or back
- Pension contributions paid by the company
Planning
- Salary and dividend mix for directors
- Timing of large purchases
- Associated companies and the profit limits
Corporation Tax penalties and how to avoid them
HMRC and Companies House charge separate penalties, and they add up quickly.
| How late | Corporation Tax return (HMRC) | Accounts (Companies House) |
|---|---|---|
| 1 day | £100 | £150 (up to 1 month late) |
| 3 months | Another £100 | £375 (1 to 3 months late) |
| 6 months | 10% of the unpaid tax HMRC estimates | £750 (3 to 6 months late) |
| 12 months | Another 10% of the unpaid tax | £1,500 (more than 6 months late) |
Late three times in a row? The £100 HMRC penalties rise to £500 each, and Companies House penalties double if your accounts are late two years running. Interest is also charged on late Corporation Tax.
Sources: GOV.UK Corporation Tax penalties, Companies House late filing penalties.
Corporation Tax return prices
Fixed fees, agreed in writing before we start. Prices exclude VAT.
Essential
One director, not VAT registered. Accounts, CT600, payroll and the director's return.
See what's includedStandard
VAT registered, up to two directors, with quarterly VAT returns and tax planning.
Check my exact priceOne-off accounts and CT600
Year-end accounts and your Corporation Tax return for one accounting period.
See one-off pricesMonthly packages include the director's Self Assessment and free company formation. Compare limited company packages.
Using an accountant vs filing your own Corporation Tax return
HMRC's own filing service for small companies has closed, so most companies now need commercial software or an accountant.
| Doing it yourself | With Fixed Fee Accountant | |
|---|---|---|
| Software | You buy and learn CT600 software | Included, with expert review |
| Reliefs | Easy to miss allowances and reliefs | Every allowance and relief checked |
| Deadlines | You track HMRC and Companies House dates | We track and file both on time |
| HMRC letters | You deal with HMRC alone | We deal with HMRC for you |
| Cost | Your time, plus software | From £75 a month + VAT, fixed |
Corporation Tax help for every type of company
Choose your situation to see how we help.
Limited companies
Accounts, CT600 and director payroll for trading companies of every size.
Accountant for limited companies →Contractors
Single-director companies, with IR35 guidance and a salary and dividend plan.
Contractor accountants →Start-ups
Your first Corporation Tax return, with formation, registration and early tax planning.
Accountant for start-ups →Small businesses
Shops, salons, trades and agencies trading through a company.
Accountant for small businesses →Construction firms
Company accounts alongside your monthly CIS returns.
Accountant for construction firms →Overseas-owned companies
UK subsidiaries and companies owned from abroad.
Overseas company set-up →Starting a new company?
Our formation service is free with any limited company package, and we register your company for Corporation Tax from day one.
Fixed fee Corporation Tax accountant
As a fixed fee Corporation Tax accountant, we agree your company's price before we start. HMRC letters, questions and planning calls are included, so your fee never changes because you needed help.
- Price agreed in writing first
- No hourly rates
- No charge for questions
Online Corporation Tax accountant
As an online Corporation Tax accountant, we connect to your accounting software and work with directors across the UK by phone, email and video, including evenings and Saturdays.
- Secure online document upload
- Evenings and Saturdays
- Support anywhere in the UK
Corporation Tax return FAQs
When is the Corporation Tax return deadline?
Your CT600 must be filed within 12 months of the end of your company's accounting period. The Corporation Tax itself is due 9 months and 1 day after the year end, so payment comes before the return deadline.
What is the Corporation Tax rate?
Corporation Tax is 19% on profits up to £50,000 and 25% on profits over £250,000. Between those limits, marginal relief gives an effective rate between the two. The limits are shared between associated companies.
How much does an accountant charge for a Corporation Tax return?
Our limited company packages, which include the accounts, CT600, director payroll and the director's Self Assessment, start at £75 a month plus VAT. A one-off set of accounts and CT600 is £499 plus VAT.
Do I still have to file a Corporation Tax return if my company made a loss?
Yes. If HMRC has sent a notice to file, you must file even if the company made a loss. Filing also lets the loss be carried forward or back to reduce tax in other years.
What happens if I file my Corporation Tax return late?
HMRC charges £100 immediately and another £100 at 3 months. At 6 months it estimates your tax and adds 10% of the unpaid amount, and another 10% at 12 months. Late payment also attracts interest.
Can I still file my CT600 through HMRC's free service?
No. HMRC's free Company Accounts and Tax Online service closed in 2025, so companies now need commercial software or an accountant to file their CT600 and accounts.
Does a dormant company need to file a Corporation Tax return?
If HMRC agrees your company is dormant, you usually don't need to file a CT600, but you must still file dormant accounts and a confirmation statement at Companies House. Dormant accounts are £150 plus VAT.
What expenses can a limited company claim?
Costs incurred wholly and exclusively for the business, such as salaries, rent, software, equipment, professional fees, travel and pension contributions. Equipment is usually claimed through capital allowances.
How can I reduce my company's Corporation Tax?
By claiming every allowance and relief, timing equipment purchases, paying employer pension contributions and choosing the right mix of salary and dividends. We review these for you every year.
Do you file the accounts with Companies House too?
Yes. Our service includes preparing and filing your statutory accounts at Companies House as well as your CT600 with HMRC.
Get your Corporation Tax return filed
Tell us about your company and we'll confirm your fixed fee, usually the same working day.