Corporation Tax deadline calculator: when is your tax due?
Enter the dates your accounts cover and the calculator gives the payment date and the Company Tax Return date, using HMRC's rules for month ends and long periods. Your dates stay on this page.
Your Corporation Tax deadlines
12 month period of account · one return- Pay Corporation Tax by
- 1 January 2028
- File the Company Tax Return by
- 31 March 2028
Dates for companies with taxable profits up to £1.5 million, from HMRC's published rules. Check them against your HMRC online account, which shows the dates HMRC holds for your company.
Our clients never have to work these dates out. Every deadline sits in their client portal and the tax is estimated long before it is due. If that is worth having, request a quote. If you only needed the number, you have it.
The rules behind the result
Corporation Tax is due 9 months and 1 day after the end of the accounting period. Where the period ends on the last day of a month, HMRC treats the tax as due on the first day of the tenth month. That is why a period ending 31 March is due on 1 January and a period ending 30 November is due on 1 September. In a leap year 28 February is not a month end, so a period ending on 28 February 2028 is due on 29 November 2028.
The Company Tax Return is due 12 months after the end of the period it covers. Where accounts run for more than 12 months, both returns are normally due 12 months after the accounts end. If the accounts run for more than 18 months the date is 30 months from the start instead.
If your taxable profits are over £1.5 million you pay by instalments, so the payment date above does not apply. HMRC explains the instalment dates. To estimate the bill itself, use our Corporation Tax calculator.
When is Corporation Tax due?
For taxable profits up to £1.5 million, 9 months and 1 day after the end of the accounting period. Where the period ends on the last day of a month, HMRC treats the tax as due on the first day of the tenth month, so a period ending 31 March is due on 1 January. Larger companies pay by instalments instead.
When is the Company Tax Return due?
12 months after the end of the accounting period it covers. The return is due later than the tax, so the payment deadline is the one to plan around.
What if my accounts cover more than 12 months?
An accounting period for Corporation Tax cannot be longer than 12 months. The first 12 months form one accounting period and the rest forms another, so you file two returns and pay the tax for each period on its own date. Both returns are normally due 12 months after the end of the accounts period.