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Company Filing Deadline Calculator
Your accounts are due at Companies House 9 months after year end, your CT600 12 months after, and your Corporation Tax is due 9 months and 1 day after. Enter your year end for exact dates.
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Your estimate
Change the numbers and press Calculate.
Estimates for 2026/27 for England, Wales and Northern Ireland taxpayers. Not personal tax advice. Scottish income tax bands differ.
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Key facts at a glance
9 months after year end
Accounts (Companies House)
12 months after year end
CT600 return
9 months and 1 day after year end
Corporation Tax payment
How it works
What the calculator assumes, so you can trust the result.
Why the dates differ
Companies House and HMRC run separate regimes. Accounts and the tax return are different filings, and payment is due before the return. Missing any of them triggers its own penalty.
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How the calculator works, step by step
Exactly what happens between pressing Calculate and seeing your result.
Enter your year-end date
Use the last day of your company's accounting period, shown on your accounts or on the Companies House record as the accounting reference date.
Dates are counted in months
Companies House accounts are due nine months after the year end, and the company tax return is due twelve months after.
Payment date is one day later
Corporation Tax is due nine months and one day after the year end, so payment falls the day after the accounts deadline.
Add the dates to your calendar
The result lists all three deadlines. Add reminders four weeks before each one.
The rates and rules we use
All figures are for the 2026/27 tax year and match GOV.UK.
| Item | Figure | Notes |
|---|---|---|
| Annual accounts (Companies House) | 9 months after year end | |
| Corporation Tax payment | 9 months and 1 day after year end | Interest runs from this date |
| Company Tax Return (CT600) | 12 months after year end | |
| Confirmation statement | Every 12 months | Not shown in this calculator |
| First accounts, new company | 21 months after incorporation | Or 9 months after the first year end if later |
The formula: Accounts = year end + 9 months. Tax payment = year end + 9 months + 1 day. CT600 = year end + 12 months.
Worked examples
Real numbers run through the same calculation, so you can check your own result.
Example 1: year end 31 March 2026
Accounts are due by 31 December 2026, Corporation Tax is due on 1 January 2027 and the CT600 by 31 March 2027.
Example 2: year end 30 June 2026
Accounts are due by 31 March 2027, tax is due on 1 April 2027 and the CT600 by 30 June 2027.
Example 3: year end 31 December 2026
Accounts are due by 30 September 2027, tax is due on 1 October 2027 and the CT600 by 31 December 2027.
Getting the most from the result
Tips
- Aim to file accounts and pay tax well before the deadline. Paying early avoids interest and gives you time to fix problems.
- Late accounts at Companies House start at a £150 penalty and rise with lateness, doubling for a second consecutive late filing.
- Late CT600 returns start with a £100 penalty, with more added over time.
What the calculator leaves out
- Assumes a private company. Public companies have shorter accounts deadlines.
- Does not show the first accounts deadline for a newly formed company.
- Large companies pay Corporation Tax in instalments, which are not shown.
- If the due date falls on a weekend, you should still aim to file or pay earlier.
Related articles
Limited company director's tax calendar
Read the full article.
Year-end accounts step by step
Read the full article.
Confirmation statement: how to file
Read the full article.
Questions people ask
Short answers to the questions that come with this calculator.
When are company accounts due?
Nine months after the accounting period end for private companies.
What is the first accounts deadline for a new company?
21 months after the date of incorporation, or nine months after the first accounting reference date, whichever is later.
When are my company accounts due?
Nine months after your accounting period ends. For a 31 March year end, that is 31 December.
When do I pay Corporation Tax?
Nine months and one day after the period end, which is a day after the accounts deadline.
Is the CT600 due at the same time as the payment?
No. The return is due twelve months after the year end, but the tax is due earlier, so you need to estimate it in advance.
What happens if I miss a deadline?
Companies House charges automatic penalties for late accounts, and HMRC charges penalties and interest for late returns and payments.
Can I change my year end?
Yes, by filing a change of accounting reference date at Companies House, though there are limits on how often and how far you can shorten or extend it.
What other deadlines does a company have?
Confirmation statement every 12 months, VAT returns quarterly, payroll submissions each pay date and the director's Self Assessment by 31 January.
Keep reading
Corporation tax
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Year-end accounts
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Confirmation statement
Annual filing.
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