Self Assessment Deadlines for 2026–2027

The 2025–2026 tax year ran from 6 April 2025 to 5 April 2026. The following dates apply to most taxpayers completing a return for that year.

These are the standard dates. Some taxpayers receive a different filing deadline, particularly where HMRC issues a return or notice to file late. Check your HMRC letter or online account if you are unsure.

Official source: HMRC Self Assessment deadlines.

Paper Tax Return Deadline: 31 October 2026

HMRC must receive most paper Self Assessment returns by 11:59 pm on 31 October 2026. Sending a return close to the deadline can be risky if postal delivery is delayed, because the return generally needs to reach HMRC by the due date.

If you have not completed a paper return, check whether you can file online instead. The standard online deadline is 31 January 2027, which gives most taxpayers more time than the paper route.

There are exceptions for some people who cannot file online or have a non-standard filing date. Trustees of registered pension schemes and certain non-resident companies, for example, can have different paper filing arrangements. Do not assume that an exception applies to your situation without checking HMRC guidance.

If you have received a return or notice to file after the usual issue period, check the deadline stated by HMRC. A different deadline may apply depending on when the notice was issued.

Online Tax Return Deadline: 31 January 2027

For most taxpayers, the deadline to submit the 2025–2026 Self Assessment return online is 31 January 2027. Online filing lets customers complete the form, save their progress and return later to check information before submitting it.

HMRC recommends gathering income records, expense information and other relevant documents before starting. Filing early can also help you find out how much tax you owe and give you more time to plan the payment.

You can access the service through the official GOV.UK website:

Sign in and file your Self Assessment tax return.

Always use the official government service and take care with messages or websites that ask for personal or financial details. HMRC will not require you to follow an unfamiliar payment link simply because a deadline is approaching.

Who Needs to Complete a Self Assessment Tax Return?

Self Assessment allows HMRC to assess income tax and certain other tax liabilities that are not fully dealt with through PAYE. Whether you need to file depends on your income and personal circumstances.

You may need to complete a return if you:

• Were self-employed as a sole trader and had gross trading income above £1,000, subject to the applicable rules and exceptions.
• Were a partner in a business partnership.
• Received taxable income from property rental or other sources that must be reported.
• Had certain savings interest, dividend income, foreign income or capital gains that need to be declared.
• Need to pay the High Income Child Benefit Charge through Self Assessment.
• Received a notice from HMRC requiring you to submit a return.

This is not a complete list. The requirement to file depends on the relevant rules and your individual circumstances. If you are unsure, use the official checker before deciding that you do not need to submit a return.

Official source: Who must send a Self Assessment tax return.

Check whether you need to send a tax return.

First-Time Filers: Registration Deadline Has Passed

People who needed to file for 2025–2026 and had not previously filed a return generally needed to notify HMRC by 5 October 2026. The same notification deadline generally applies to people who were registered previously but did not need to submit a return for the 2024–2025 tax year.

As that date has passed, anyone who believes they should have registered but has not done so should act promptly. HMRC says that if you register after 5 October 2026, it will send a letter or email giving you a different filing deadline, which will be three months from the date of that communication.

The normal deadline to pay tax owed remains 31 January 2027. A later filing date does not automatically extend the payment deadline.

People who previously registered but did not file last year may need to reactivate their account. Check your status through HMRC rather than assuming your registration is still active.

Official source: Registering for Self Assessment.

When Must You Pay Your Tax Bill?

The standard deadline to pay tax owed for the 2025–2026 tax year is 31 January 2027. This is separate from the paper filing deadline, which falls on 31 October 2026.

Some taxpayers must also make payments on account. These are advance payments towards a future tax bill and usually fall due on 31 January and 31 July. Whether payments on account apply depends on your tax position and the relevant rules.

If you file early, you can find out what you owe sooner and budget for the payment. You do not normally have to pay the entire bill immediately just because you submitted your return early.

If you think you will struggle to pay by the deadline, contact HMRC as soon as possible and check whether you can arrange to pay in instalments. Do not assume that a payment plan has been approved until HMRC confirms the arrangement.

Official guidance: How to pay your Self Assessment tax bill.

Can HMRC Collect Your Tax Through Your PAYE Tax Code?

Some taxpayers who also have PAYE employment income may be able to have a Self Assessment bill collected through their tax code. For the 2025–2026 return, the standard deadline to submit the return for this option is 30 December 2026.

This method is subject to eligibility conditions, including limits relating to the amount owed and the type of income involved. It is not available to every taxpayer, so check HMRC guidance before relying on it.

If you miss the 30 December date, you may still be able to file online by 31 January 2027, but you will need to use another payment method if you cannot use tax-code collection.

Official source: HMRC payment methods.

What Are the Penalties for Filing Late?

Missing a Self Assessment filing deadline can lead to penalties. Under the standard rules, a return filed late can attract an initial fixed penalty of £100, even if there is no tax to pay.

Further late-filing penalties may apply when a return remains outstanding:

• More than three months late: Daily penalties of £10 may apply for up to 90 days, potentially adding £900.
• More than six months late: A further penalty may be charged, generally the greater of £300 or 5% of the tax due.
• More than twelve months late: Another penalty may apply, generally the greater of £300 or 5% of the tax due, with higher penalties possible in some cases involving deliberate withholding of information.

Late payment can result in separate interest and penalties. The precise consequences depend on the circumstances. If you have a reasonable excuse for missing a deadline, HMRC provides a process for appealing a penalty, but acceptance is not automatic.

Official guidance: Self Assessment penalties.

Winter Fuel Payment and the 2025–2026 Tax Return

HMRC has highlighted an additional point for customers who received a Winter Fuel Payment in 2025–2026, or a Pension Age Winter Heating Payment in Scotland, and are required to complete Self Assessment.

Where possible, the payment will be pre-populated in the online 2025–2026 tax return. Customers should check the entry and add it manually if it is missing. People filing on paper must include the relevant amount themselves.

Under the announced rules, customers with total income over £35,000 will repay the payment through their Self Assessment tax bill. The amount and treatment should be checked against the official HMRC instructions and the taxpayer's circumstances.

Official source: HMRC Self Assessment reminder, 8 October 2026.

High Income Child Benefit Charge: Check Your Online Return

HMRC has also announced that around 300,000 Self Assessment customers liable for the High Income Child Benefit Charge will have their own or their partner's Child Benefit payment details pre-populated in their online return, where applicable.

This is intended to make it easier to report the relevant information accurately. Taxpayers should still review the details and correct or add information if it is missing or incorrect.

Some eligible customers may be able to pay the charge monthly through PAYE, which can adjust their tax code. Check the official HMRC guidance to establish whether that option is available for your circumstances.

Official source: High Income Child Benefit Charge guidance.

Making Tax Digital: Do You Still Need to File?

HMRC has confirmed that taxpayers already signed up to Making Tax Digital for Income Tax still need to submit their 2025–2026 Self Assessment return and pay any tax owed by 31 January 2027.

Making Tax Digital changes how eligible people keep records and report income for the relevant tax years. It does not remove the requirement to submit the ordinary Self Assessment return for the tax year before they begin using the new system.

People affected by Making Tax Digital should check the official rules and software requirements that apply to their business or property income.

Official source: Making Tax Digital for Income Tax: Submit your tax return.

How to Prepare Your Self Assessment Return

Getting your records ready can reduce errors and make the process easier. The documents you need depend on the income you received during the tax year.

• Your National Insurance number and Self Assessment login details.
• Your Unique Taxpayer Reference, if applicable.
• Employment records such as P60 or P45 information.
• Self-employment income, invoices and allowable business expenses.
• Property rental income and relevant expenses.
• Bank interest, dividend statements and details of other taxable income.
• Information about capital gains, pension contributions and Gift Aid donations where relevant.
• Records of tax already paid and any payments on account.
• Relevant benefit payment details if they need to be reported on your return.

Check every figure before submitting the return and keep records that support the information you provide. If you are uncertain about a tax rule or expense, consult HMRC guidance or a qualified tax adviser.

Frequently Asked Questions

Final Summary

The main dates for the 2025–2026 UK Self Assessment tax return are 31 October 2026 for most paper returns, 30 December 2026 for eligible taxpayers who want tax collected through their PAYE code, and 31 January 2027 for most online returns and tax payments.

Taxpayers should check whether they need to file, gather their records, review any pre-populated benefit details and submit an accurate return. If you missed a registration deadline or are worried about paying the bill, consult HMRC as soon as possible rather than waiting until January.