When Are UK Tax Returns Due? Key Deadlines to Know

Understanding tax obligations in the United Kingdom is important for financial management. The UK tax system, overseen by His Majesty’s Revenue and Customs (HMRC), operates on annual cycles with clear deadlines for filing tax returns. Adhering to these dates ensures compliance and avoids potential penalties. This overview clarifies key aspects of UK tax returns.

Who Must File

Not every individual in the UK needs to file a Self Assessment tax return, as tax is often automatically deducted from wages and pensions through the Pay As You Earn (PAYE) system. However, a Self Assessment tax return is required if you have other sources of income not taxed at source. This includes:

Self-employed individuals operating as a sole trader with gross income exceeding £1,000 before expenses.
Income from renting out a property exceeding £2,500.
Untaxed income, such as tips or commission, totaling over £2,500.
Income from savings or investments reaching £10,000 or more before tax.
A need to pay Capital Gains Tax.
Company directors.
Individuals claiming Child Benefit with income over a certain threshold.
Individuals with foreign income.
Individuals with a total taxable income exceeding £150,000.

Key Deadlines

The UK tax year operates from April 6th of one year to April 5th of the following year. For example, the tax year ending April 5, 2025, has associated deadlines in late 2025 and early 2026. Individuals new to Self Assessment must register with HMRC by October 5th following the end of the tax year in which they became eligible.

The method of filing determines the submission deadline for your tax return. Paper tax returns must be received by HMRC by October 31st following the end of the tax year. For online submissions, the deadline is January 31st of the subsequent year.

How to Submit Your Return

Once your Self Assessment tax return is prepared, there are two primary methods for submission: online or via paper. The online method is preferred by HMRC and offers a later filing deadline. To submit online, individuals use their Government Gateway account to access HMRC’s online service or approved third-party software.

For paper filing, the official SA100 tax return form can be downloaded from the HMRC website or requested directly from HMRC. After completing the form, it must be mailed to HMRC by the specified deadline. Ensure all relevant sections are accurately completed based on your financial records.

Paying Your Tax Bill

Paying any tax due is a distinct step from filing the return, though both share important deadlines. The main payment deadline for any outstanding tax from the previous tax year is January 31st. This date also marks the due date for the first “payment on account,” an advance payment towards your tax bill for the current tax year, if your tax liability exceeds £1,000.

A second payment on account, if applicable, is due on July 31st. HMRC offers various methods for paying your tax bill, including direct bank transfer (Faster Payments, Bacs), Direct Debit, or online payment using a debit card. Payments can also be made by cheque through the post or, in some cases, through your tax code if the amount owed is less than £3,000 and the online return is filed by December 30th.

What Happens If You Miss a Deadline

Failing to meet Self Assessment deadlines can result in penalties from HMRC. An automatic penalty of £100 is applied if an online tax return is even one day late, even if no tax is owed. This initial penalty can escalate significantly if the return remains outstanding.

After three months of continued lateness, daily penalties of £10 per day can be applied, up to a maximum of £900. Further penalties, such as 5% of the tax due or £300 (whichever is greater), may be levied after six months and again after twelve months. Additionally, late payment of tax incurs penalties, with 5% of the unpaid tax charged after 30 days, another 5% after six months, and a further 5% after twelve months, alongside interest charges on the overdue amount.