When is corporation tax due

For most companies corporation tax is due nine months and one day after the end of the accounting period, which is three months before the company tax return has to be filed. Each payment must quote the 17 character payment reference for the accounting period it relates to, and that reference changes every period.

When exactly is corporation tax due?

Section 59D of the Taxes Management Act 1970 says 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. GOV.UK expresses this as nine months and one day after the end of the accounting period, and it applies to companies with taxable profits of up to £1.5 million.

Accounting period ends	Payment due	Return due
31 December 2025	1 October 2026	31 December 2026
31 March 2026	1 January 2027	31 March 2027
30 June 2026	1 April 2027	30 June 2027

The deadline is tied to the accounting period, not to the company’s accounts. Where accounts run for more than 12 months there are two accounting periods and therefore two payment dates, which is common in a company’s first year. Our page on your company’s first corporation tax return works through that case.

Why is the tax due before the return?

The filing date for a company tax return is usually 12 months after the end of the accounting period, under paragraph 14 of Schedule 18 to the Finance Act 1998. The payment date comes three months earlier. In practice that means the company must work out, or at least estimate, its liability and pay it before the return is finished.

The law deals with the mismatch in two ways. If the company pays too much, section 59D(2) provides for the excess over the tax payable shown in the return to be repaid. If it pays too little, interest runs from the due date under section 87A of the same Act until the balance is paid. Interest is charged even if the return itself is filed on time, so a company that waits for the final computation before paying will usually owe interest.

The practical answer is to have the computation done within nine months of the year end, or to pay a careful estimate on time and settle any difference when the return is filed. GOV.UK confirms HMRC may pay interest where tax is paid early, and charges interest where it is paid late. See our page on interest on late and overpaid corporation tax.

Which companies have to pay earlier?

Companies with taxable profits over £1.5 million pay by instalments instead of a single payment, with separate rules for profits between £1.5 million and £20 million and for profits over £20 million. These dates fall during and shortly after the accounting period, well before the nine month date. Our page on quarterly instalment payments covers which companies are caught and when each instalment falls.

What is the payment reference and where do you find it?

GOV.UK says every corporation tax payment must use the company’s 17 character corporation tax payment reference number for the accounting period being paid. The reference changes with each accounting period, so a new one is needed every time. It can be found:

• on the notice to deliver a company tax return;
• on any reminder from HMRC;
• in the company’s HMRC online account, by choosing to view the corporation tax statement, then accounting periods, then the correct period.

HMRC warns that a wrong reference can delay the payment or cause it to be used against a different tax bill. If that happens the company can contact corporation tax general enquiries and ask for the payment to be moved. Late filing penalties are paid using the reference for the accounting period the penalty relates to.

The reference is not the company’s 10 digit Unique Taxpayer Reference on its own. Because the period changes every year, it should be checked each time rather than copied from the last payment.

How can the tax be paid, and how long does each method take?

GOV.UK lists these timings for corporation tax payments:

• same or next day: approving a payment through the company’s online bank account, Faster Payments or CHAPS, debit or corporate credit card online, and paying at a bank or building society;
• three working days: Bacs, or Direct Debit where one has been set up for HMRC before;
• five working days: Direct Debit set up for the first time.

Corporation tax cannot be paid by post. Direct Debit cannot be used for payments over £20 million. Bank transfers go to the account named on the notice to deliver or HMRC reminder; GOV.UK says to use HMRC Cumbernauld if unsure. Groups can pay under a Group Payment Arrangement, and HMRC provides a CHAPS enquiry form for a single payment covering several companies for the same accounting period.

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

GOV.UK says that if the deadline falls on a weekend or bank holiday, the payment must reach HMRC on the last working day before it, unless the company is paying by Faster Payments through online or telephone banking. Section 87A(2) of the Taxes Management Act 1970 confirms that interest runs from the due date even where that date is a non business day.

Illustration only. A company with a 31 March 2026 year end has a payment date of 1 January 2027, which is a bank holiday. A Bacs payment needs to reach HMRC by Thursday 31 December 2026. Bacs usually takes three working days, and the Christmas Day and substitute Boxing Day bank holidays fall in the days before, so the payment has to be started earlier than the calendar suggests. A Faster Payment can be made on 1 January 2027 itself.

What if there is nothing to pay, or the company cannot pay?

If no corporation tax is due, GOV.UK asks companies to tell HMRC using the nil to pay form; otherwise HMRC will send payment reminders. The company must still file its return.

If the company cannot pay in full, it should contact HMRC before the deadline. A Time to Pay arrangement can spread the debt, but interest still runs on the unpaid balance; GOV.UK notes that paying more quickly means paying less interest.

What mistakes come up most often?

• Treating the 12 month filing deadline as the payment deadline and paying three months late.
• Reusing last year’s payment reference saved as a payee in online banking. GOV.UK specifically warns that banks keep the last reference used.
• Sending a Bacs or first Direct Debit payment too close to the deadline.
• Forgetting that a long first period of accounts creates two payment dates.
• Assuming a company with a large one off profit can still pay in one sum; crossing the £1.5 million threshold changes the timetable.
• Not filing a nil to pay form, then ignoring the reminders that follow.

For all corporation tax dates in one place, see our corporation tax deadlines page, and for what goes in the return itself see the CT600 explained.

If HMRC opens a check into your return, tax investigation insurance pays your accountant’s fees. Solar Protect cover pays up to £100,000 with no excess; it never pays tax, interest or penalties. Read how our cover works or get a quote.

Related Accountapedia entries

• How to pay HMRC and use the right reference
• VAT return and payment deadlines
• Corporation tax instalments for very large companies
• Group payment arrangements for corporation tax
• Corporation tax late filing penalties

Sources

• legislation.gov.uk: Act 1970 c. 9, section 59D
• GOV.UK: Pay corporation tax
• legislation.gov.uk: Act 1998 c. 36, schedule 18
• GOV.UK: Company tax returns
• legislation.gov.uk: Act 1970 c. 9, section 87A
• GOV.UK: Bank details
• GOV.UK: Direct debit
• GOV.UK: Payments for a group of companies
• GOV.UK: Tell hmrc no payment due
• GOV.UK: Bank holidays

Reviewed by Christine Anderson, Broker, Solar Protect. Last reviewed 19 October 2026. Part of Accountapedia, the Solar Protect guide to UK tax and accounting. This page is general information, not personalised advice.