Corporation Tax Deadlines: UK Limited Companies 2026/27

Most UK limited companies must pay Corporation Tax nine months and one day after the end of their Corporation Tax accounting period. The Company Tax Return is normally due later—12 months after the accounting period ends.

Those two deadlines are commonly confused. A company usually has to calculate and pay its tax before the statutory filing deadline for the return.

Corporation Tax deadlines at a glance

Large companies can have different Corporation Tax payment dates because quarterly instalment rules may apply.

Corporation Tax payment example

A company’s accounting period ends on 31 December 2026. If the normal payment rule applies:

• Corporation Tax is due by 1 October 2027; and
• the Company Tax Return is due by 31 December 2027.

The corresponding Companies House accounts deadline may be 30 September 2027 if the financial year and accounting period align, but the company should check its registered deadline rather than assume the dates are identical.

What is the accounting period?

The Corporation Tax accounting period is the period covered by the Company Tax Return. It is normally 12 months and often matches the company’s financial year, but it cannot be longer than 12 months.

A newly incorporated company can have accounts covering more than 12 months. That may create two Corporation Tax accounting periods and two payment calculations, even though Companies House receives one set of first accounts.

When quarterly instalment payments apply

Companies with taxable profits above the applicable thresholds may have to pay Corporation Tax in instalments rather than nine months and one day after year end. HMRC’s headline threshold is £1.5 million of taxable profits, with separate rules for companies whose profits exceed £20 million.

The thresholds can be reduced where the company has associated companies and can be affected by the length of the accounting period. A company close to a threshold should calculate its status early rather than wait until the return is prepared.

Corporation Tax payment versus filing

The key dates are separate:

• Payment deadline: when cleared funds must reach HMRC.
• Return deadline: when the CT600, tax computations and accounts must be delivered to HMRC.
• Accounts deadline: when statutory accounts must reach Companies House.

Paying the tax does not file the return, and filing accounts at Companies House does not submit the Company Tax Return to HMRC.

How to find the exact deadline

Check the company’s accounting-period dates in its HMRC online account and compare them with the accounting reference date at Companies House. HMRC reminders and the notice to deliver a return also contain relevant information.

The 17-character Corporation Tax payment reference changes for each accounting period. Using an old reference can delay allocation of the payment.

If the deadline is a weekend or bank holiday

The payment must normally reach HMRC by the deadline. GOV.UK advises businesses to make sure payment reaches HMRC on the last working day before a weekend or bank-holiday deadline, unless paying by Faster Payments through online or telephone banking.

Late payment and late filing

HMRC charges interest when Corporation Tax is paid late. Separate fixed and tax-related penalties apply to a late Company Tax Return. Companies House also imposes penalties for late statutory accounts.

A company can therefore face more than one consequence from the same delayed year-end process. If payment cannot be made on time, contact HMRC before the deadline to discuss available support.

Does a company with no tax still file?

If HMRC has issued a notice to deliver a Company Tax Return, the company must normally submit it even where it made a loss or has no Corporation Tax to pay. A dormant company should notify HMRC and follow the specific dormant-company procedure.

Planning checklist

• Confirm the accounting period and Companies House year end.
• Estimate taxable profit before the payment date.
• Check associated-company and instalment-payment rules.
• Allow time for the chosen payment method to clear.
• Use the correct 17-character payment reference.
• File the return and statutory accounts by their separate deadlines.

Frequently asked questions

Is Corporation Tax due nine months after year end?

The normal rule is nine months and one day after the end of the accounting period.

Can the Company Tax Return be filed after the tax is paid?

Yes. The usual return deadline is three months later, but the company must calculate its liability accurately enough to pay on time.

Do all companies pay annually?

No. Companies within the quarterly-instalment regime pay on different dates.

Official sources

See Pay your Corporation Tax bill, Company Tax Returns and Accounts and tax returns for private limited companies.

How to make the payment

After confirming the deadline, see our Corporation Tax payment-method guide.