Key Tax Deadlines from September 2026 to January 2027: What Businesses Need to Know.

Most businesses do not have one tax deadline.

They have several.

A limited company may be dealing with Corporation Tax, VAT and payroll at the same time. A construction business may also have CIS returns. A director or sole trader may have personal Self Assessment obligations alongside the company’s deadlines.

And from April 2026, some sole traders and landlords also have Making Tax Digital for Income Tax quarterly updates to consider.

The important thing is that not every deadline below will apply to every business.

Your exact dates depend on your business structure, accounting period, VAT quarters, payroll arrangements and personal tax position.

The recurring deadlines businesses should recognise.

Before looking month by month, there are several patterns worth understanding.

VAT-registered businesses can check their individual filing dates through their VAT online account.

HMRC’s VAT Return deadline guidance explains the normal one-month-and-seven-day rule.

Employers can also check the PAYE payment deadlines , while contractors can review HMRC’s CIS monthly return guidance .

September 2026 tax deadlines.

October 2026 tax deadlines.

October contains several of the more important one-off deadlines in the autumn tax calendar.

The 5 October Self Assessment registration deadline

If you need to file a Self Assessment return for 2025/26 and have not previously registered, 5 October is an important date.

This can apply where, for example, somebody became self-employed, received untaxed income or realised gains that need to be reported.

HMRC’s Self Assessment deadline guidance also confirms that paper returns must normally reach HMRC by 31 October and online returns by 31 January.

November 2026 tax deadlines.

For businesses and landlords within Making Tax Digital for Income Tax, November contains one of the most important new dates of the year.

7 November: the second MTD quarterly update

Making Tax Digital for Income Tax became mandatory from April 2026 for the first group of qualifying sole traders and landlords.

Under the standard quarterly periods, the second update covers records from 6 April to 5 October 2026 and must be submitted by 7 November.

If calendar quarters have been elected, the update normally covers 1 April to 30 September, but the filing deadline remains 7 November.

HMRC’s current MTD quarterly update guidance confirms the 7 November deadline.

Landlords and sole traders who want more detail can also read our specialist Property Tax Advice guide: Making Tax Digital for Income Tax: Frequently Asked Questions .

December 2026 tax deadlines.

Why 30 December matters for some Self Assessment taxpayers

The normal online filing deadline is still 31 January 2027.

However, somebody who owes less than £3,000 and wants HMRC to consider collecting the liability through their PAYE tax code normally needs to submit the return online by 30 December.

Missing 30 December does not mean the Self Assessment return is automatically late.

It simply means that this particular payment option may no longer be available.

January 2027 tax deadlines.

January is the month most people associate with tax deadlines, and for good reason.

Does Making Tax Digital change the 31 January 2027 Self Assessment deadline?

This is an important point for people who entered Making Tax Digital for Income Tax in April 2026.

Your Self Assessment return due on 31 January 2027 relates to the 2025/26 tax year.

That tax year was before mandatory MTD for Income Tax began.

HMRC therefore says the 2025/26 tax return should still be submitted in the normal way.

The first mandatory MTD tax year is 2026/27, and the final tax return for that year is due by 31 January 2028.

Why Corporation Tax deadlines depend on your year end.

Unlike Self Assessment, Corporation Tax does not have one universal annual payment date for every company.

Your deadlines normally follow your company’s own Corporation Tax accounting period.

For companies with taxable profits within the normal payment regime:

• Corporation Tax is normally payable 9 months and 1 day after the accounting period ends; and
• the Company Tax Return is normally due 12 months after the accounting period ends.

This is why, for example, a company with a 31 March 2026 year end would normally pay Corporation Tax on 1 January 2027 but not file the corresponding Company Tax Return until 31 March 2027.

HMRC explains the distinction in its Company Tax Return guidance .

What about larger companies?

Companies with annual taxable profits above the relevant large-company threshold may need to pay Corporation Tax by quarterly instalments rather than waiting nine months and one day.

HMRC’s standard large-company threshold is £1.5 million of annual taxable profits, while a separate very-large-company regime applies above £20 million.

Those thresholds can be reduced where there are associated companies, so they should not be treated as simple standalone turnover tests.

See HMRC’s Corporation Tax instalment guidance for large companies .

Other specialist deadlines may apply.

A general business calendar cannot cover every specialist tax regime.

Depending on your circumstances, additional dates may apply for areas such as:

• PAYE Settlement Agreements;
• CT61 returns;
• employment intermediary reporting;
• Plastic Packaging Tax;
• Inheritance Tax;
• trust reporting;
• non-resident landlords; and
• large-company Corporation Tax instalments.

Non-resident landlords and letting agents

The Non-Resident Landlord Scheme has quarterly reporting and payment obligations for letting agents and, in some circumstances, tenants deducting tax from rents.

Our specialist Expat Tax Advice team explains the regime in: Understanding the UK’s Non-Resident Landlord Scheme .

Do not plan tax deadlines around the deadline itself.

Knowing a filing date is useful.

Knowing what information, cash and decisions are needed several weeks before that date is much more useful.

For example, a 31 January Self Assessment payment should not ideally come as a surprise on 30 January.

Likewise, a VAT bill should be considered when managing cash during the quarter rather than only when the return is ready to submit.

If customers are paying slowly, tax liabilities do not automatically move with them.

Our guide Late-Paying Customers: How to Protect Your Small Business Cash Flow looks at how credit control and cash-flow planning can help prevent customer payment delays from creating wider pressure.

RiverView view: deadlines should be checkpoints, not emergencies.

Tax deadlines are unavoidable.

Last-minute tax emergencies are not always unavoidable.

Keeping bookkeeping current, reconciling accounts regularly and reviewing expected liabilities throughout the year makes it much easier to identify what needs to be filed and what needs to be paid.

It also gives business owners a much clearer picture of the cash they can genuinely afford to spend.

RiverView Portfolio’s Business & Financial Strategy support is designed to help businesses use their financial information throughout the year rather than only at filing time.

Our article Do You Put Yourself First When Looking at Your Numbers? also looks at why useful financial information should support decisions before the year has already passed.

Your September-to-January tax checklist.

1. Check which deadlines actually apply to you. Your VAT quarters, company year end, payroll cycle and personal tax position will determine your real calendar.
2. Add recurring PAYE, VAT and CIS dates to your calendar. Do not rely on remembering the same monthly or quarterly deadline each time.
3. Check whether you need to register for Self Assessment by 5 October. New tax obligations should be dealt with before the filing deadline approaches.
4. If you are within MTD, prepare for 7 November. The second quarterly update is required even though HMRC is not applying quarterly penalty points during 2026/27.
5. Review your expected January tax bill before Christmas. Waiting until January to calculate the liability leaves little time to prepare the cash.
6. Check Corporation Tax payment and filing dates separately. They are usually not the same date.
7. Allow for weekends and bank holidays. Several deadlines in this period fall on weekends, and payment clearing times can matter.
8. Keep your bookkeeping current. Deadlines become much easier to manage when the underlying records are already complete.

Five busy months are coming.

Between September and the end of January, businesses can face VAT, PAYE, CIS, Corporation Tax, MTD and Self Assessment deadlines.

Not all of those dates will apply to you.

But the ones that do should not come as a surprise.

September and October are a good time to review the next few months as a whole rather than dealing with each tax obligation only when HMRC sends a reminder.

That means identifying what needs to be filed, estimating what needs to be paid and making sure the cash will be available when the deadline arrives.

Because a tax deadline is much easier to manage when it is part of the plan rather than an interruption to it.

Frequently asked questions.

This article provides general information only and does not constitute tax, legal or financial advice. The deadlines that apply depend on the taxpayer’s business structure, accounting periods, VAT periods, payroll arrangements and individual circumstances. Current HMRC guidance and your own HMRC account should be checked for the exact filing and payment dates that apply to you.