When do I pay Corporation Tax?

Taxes Management Act 1970, section 59D(1): corporation tax for an accounting period is due and payable on the day following the expiry of nine months from the end of that period. Section 59D(2): if the tax payable is exceeded by amounts already paid, as stated in the company tax return, the excess is repaid. Section 59D(5): the section has effect subject to section 59E (instalments) and section 357YQ of the Corporation Tax Act 2010.

HMRC's manual (CTM01800) says CT is normally due and payable nine months and one day from the end of an accounting period. Where the period ends on the last day of a calendar month, the normal due date is the first day of the tenth month. Where it ends on some other day, the normal due date is the day after the correspondingly numbered day in the ninth following month. Where the ninth following month has no such day, the normal due date is the first day of the tenth following month. HMRC's examples: 31 March 1999 gives 1 January 2000; 1 July 1999 gives 2 April 2000; 28 May 2000 gives 1 March 2001; 31 May 2000 gives 1 March 2001. CTM92010 says the same, and that for earlier accounting periods the extra day beyond nine months was allowed by concession.

SourcesThe law·HMRC

Finance Act 1998, Schedule 18, paragraph 14: the filing date for a company tax return is the last day of whichever of these periods ends last: twelve months from the end of the period the return covers; if the relevant period of account is not longer than 18 months, twelve months from the end of that period; if it is longer than 18 months, 30 months from its beginning; three months from the date the notice requiring the return was served. The relevant period of account is the one in which the last day of the accounting period falls. So the return can be due later than 12 months after the period ends. The payment date does not move with it.

SourcesThe law·HMRC

Taxes Management Act 1970, section 87A(2): interest applies even if the date when the tax becomes due and payable is a non-business day within the meaning of section 92 of the Bills of Exchange Act 1882. GOV.UK's pay page gives the last-working-day advice and the Faster Payments exception.

SourcesThe law·GOV.UK

Taxes Management Act 1970, section 87A(1): corporation tax carries interest at the rate applicable under section 178 of the Finance Act 1989 from the date when the tax becomes due and payable until payment. The general late payment interest rules in Finance Act 2009, section 101, do not apply to corporation tax. GOV.UK says interest runs from the day after the tax should have been paid until the date you pay it. HMRC's COTAX manual (COM80010) says the normal due date is a non-interest bearing date, so late payment interest is calculated from the day after it to the effective date of payment.

The rate for unpaid corporation tax, other than large companies' instalments, is set by regulation 3ZB of the Taxes (Interest Rate) Regulations 1989 (SI 1989/1297), inserted by SI 1998/3176. As inserted, its formula was reference rate plus 2.5. From 6 April 2025 it is reference rate plus 4 (SI 2025/386). The revised text on legislation.gov.uk does not yet show regulation 3ZB. The reference rate is the official bank rate set at the most recent meeting of the Bank of England's Monetary Policy Committee (SI 2009/2032).

HMRC's rates page, table "Corporation Tax Self Assessment, from normal due date": 8.50% from 6 April 2025, 8.25% from 28 May 2025, 8.00% from 27 August 2025, 7.75% from 9 January 2026. Its table for early payments of corporation tax not due by instalments shows 3.50% from 29 December 2025.

SourcesThe law·HMRC·GOV.UK