Self Assessment: What you need to know before 31st January

31st January 2026 marks the deadline for filing your Self Assessment tax returns for the 2024/25 tax year and any tax owed. This covers any income earned between 6 April 2024 and 5 April 2025.

This is also the final date to pay any tax you owe for the 2024/25 period, including any balancing payment for 2024/25 and, where applicable, your first payment on account for the 2025/26 tax year.

This article contains all the information you should need ahead of the deadline, you can also find our handy Self Assessment Tax Return Checklist here:

Who needs to file a Self Assessment?

You may need to submit a Self Assessment tax return if you’ve earned income that hasn’t already been taxed, or if your personal or financial circumstances meet certain HMRC criteria.

For the 31 January 2026 deadline, you’ll need to file a Self Assessment if any of the following apply to you:

• You’re self‑employed as a sole trader and have earned more than £1,000 in gross income during the 2024/25 tax year. This threshold relates to HMRC’s Trading Allowance and applies to small businesses.
• You’re a partner in a business partnership. If you share ownership and profits, you’ll need to declare your share of the partnership’s income.
• You receive rental income from UK or overseas property that must be declared to HMRC. This includes traditional buy‑to‑lets, holiday lets, Airbnb income, and renting out rooms in your home above the £7,500 Rent a Room allowance.
• You’re a company director and receive untaxed income, dividends or benefits, unless you’re a director of a non‑profit organisation and receive no salary or benefits.
• You earn untaxed additional income, via things like freelance work, consulting, digital services, content creation, tutoring, online sales or affiliate commissions.
• You receive savings interest, dividends or investment income over HMRC’s tax‑free allowances.
• You receive foreign income, even if it’s only a small amount or tax has already been paid overseas.
• You’ve made capital gains above HMRC thresholds by selling assets such as shares, property, cryptoassets or other investments.
• You’re liable for the High-Income Child Benefit Charge, which applies when your income exceeds HMRC’s specified threshold.
• HMRC has issued you with a notice to file, even if your income falls below the standard reporting thresholds.

The above is not an exhaustive list, and HMRC may require you to complete a self-assessment tax return for other reasons.

What documents do you need before you submit?

To complete your Self Assessment, HMRC expects you to keep clear and accurate records of your income and any allowable expenses. Having these to hand can make the process quicker and far less stressful:

• Your Unique Taxpayer Reference (UTR) and Government Gateway login details
• Employment and self‑employment income records, including P60s or P45s, invoices, sales records, expenses and bank statements
• Rental income and property expense records
• Details of savings interest, dividends and investment income
• Records of any trading, crypto or side‑income activity

How can we help

Filing a Self Assessment tax return can feel overwhelming, especially with HMRC’s complex rules and deadlines. Whether you’re a sole trader, landlord, company director or earning additional income, we’re here to take the pressure off.

We’ll ensure your tax return is accurate, compliant and submitted on time, helping you avoid penalties and make the most of any allowances and reliefs you’re entitled to.