taxontime

Corporation Tax

Corporation Tax deadline: when to pay and when to file

Corporation Tax is due 9 months and 1 day after the end of your accounting period. The Company Tax Return (CT600) is due 12 months after it. Enter your year end below, or find it in the table for every 2026 and 2027 month end.

Published 16 October 2026 · Rules from GOV.UK: pay your Corporation Tax bill and Company Tax Returns

Companies House accounts
31 December 2026
9 months after year end
Corporation Tax payment
1 January 2027
9 months and 1 day after year end
Company Tax Return (CT600)
31 March 2027
12 months after year end

Assumes a private company that is not paying Corporation Tax by instalments and is past its first accounts. For your company's actual dates from the Companies House register, plus VAT, PAYE and CIS, use the full deadline generator .

Deadlines by year end, 2026 and 2027

Private company, not in quarterly instalments, past its first accounts. The Companies House accounts column is included because it falls one day before the Corporation Tax payment and is often confused with it.

Year endAccounts to Companies HouseCorporation Tax paymentCT600 filing
31 Jan 202631 Oct 20261 Nov 202631 Jan 2027
28 Feb 202630 Nov 20261 Dec 202628 Feb 2027
31 Mar 202631 Dec 20261 Jan 202731 Mar 2027
30 Apr 202631 Jan 20271 Feb 202730 Apr 2027
31 May 202628 Feb 20271 Mar 202731 May 2027
30 Jun 202631 Mar 20271 Apr 202730 Jun 2027
31 Jul 202630 Apr 20271 May 202731 Jul 2027
31 Aug 202631 May 20271 Jun 202731 Aug 2027
30 Sep 202630 Jun 20271 Jul 202730 Sep 2027
31 Oct 202631 Jul 20271 Aug 202731 Oct 2027
30 Nov 202631 Aug 20271 Sep 202730 Nov 2027
31 Dec 202630 Sep 20271 Oct 202731 Dec 2027
31 Jan 202731 Oct 20271 Nov 202731 Jan 2028
28 Feb 202730 Nov 20271 Dec 202729 Feb 2028
31 Mar 202731 Dec 20271 Jan 202831 Mar 2028
30 Apr 202731 Jan 20281 Feb 202830 Apr 2028
31 May 202729 Feb 20281 Mar 202831 May 2028
30 Jun 202731 Mar 20281 Apr 202830 Jun 2028
31 Jul 202730 Apr 20281 May 202831 Jul 2028
31 Aug 202731 May 20281 Jun 202831 Aug 2028
30 Sep 202730 Jun 20281 Jul 202830 Sep 2028
31 Oct 202731 Jul 20281 Aug 202831 Oct 2028
30 Nov 202731 Aug 20281 Sep 202830 Nov 2028
31 Dec 202730 Sep 20281 Oct 202831 Dec 2028

The three dates, explained

Corporation Tax payment — 9 months and 1 day
Counted from the last day of the accounting period. A 31 March year end gives 1 January; a 30 June year end gives 1 April; a 31 December year end gives 1 October. HMRC must have received the money by then.
Company Tax Return (CT600) — 12 months
The return, computations and accounts go to HMRC online within 12 months of the period end. Late returns attract an automatic £100 penalty, another £100 after 3 months, and tax-geared penalties after 6 and 12 months. Estimate them with the penalty calculator.
Accounts to Companies House — 9 months
A separate filing to a separate body, due 9 months after the accounting reference date (first accounts are usually 21 months after incorporation). Missing it triggers a Companies House late filing penalty from £150. If you genuinely cannot make it, you can apply to extend the accounts deadline — but that does not move the Corporation Tax dates.

Two exceptions

  • Large companies pay by instalments. If taxable profits exceed £1.5 million (divided between associated companies), tax is paid in four quarterly instalments, the first of them before the period has ended. See GOV.UK: paying in instalments.
  • A first period longer than 12 months is split. HMRC creates two accounting periods, each with its own payment date and CT600. The deadline generator handles this split when you enter your incorporation date.

Frequently asked questions

When is Corporation Tax due?

For most companies, Corporation Tax must be paid 9 months and 1 day after the end of the accounting period. If your accounting period ends on 31 March 2026, the payment deadline is 1 January 2027. The Company Tax Return (CT600) is due 12 months after the period ends, so the payment comes before the return.

Why is the payment deadline before the filing deadline?

The two deadlines come from different rules. You pay based on your own calculation of the profit (HMRC calls this "pay and file"), then confirm the figures in the CT600 up to three months later. In practice most companies prepare the return first so they know the amount to pay.

What if my accounting period is longer than 12 months?

A Corporation Tax accounting period cannot be longer than 12 months, so a long first period of accounts is split into two: one period of 12 months and a second for the remaining days. Each has its own payment deadline and its own CT600. Companies House still only needs one set of accounts for the whole period.

What happens if I pay Corporation Tax late?

HMRC charges interest from the day after the deadline until you pay, at the Bank of England base rate plus 4%. There is no fixed late payment penalty for Corporation Tax itself, but filing the CT600 late attracts penalties starting at £100, rising the longer it is outstanding.

Do large companies have different deadlines?

Yes. Companies with taxable profits over £1.5 million (reduced where there are associated companies) usually pay in quarterly instalments, starting before the accounting period ends. The 9 months and 1 day rule applies to everyone else.

What if the deadline falls on a weekend or bank holiday?

The deadline does not move. Make sure the payment reaches HMRC by the last working day before it, and allow for bank processing times.

Related

Example year end 31 March 2026: accounts 31 December 2026, payment 1 January 2027, CT600 31 March 2027. General information, not advice. TaxOnTime is not affiliated with HMRC.