Self assessment: who has to file a tax return and when
Many people on PAYE never need a tax return. Savings, investments, a second property, a large gain or the High Income Child Benefit Charge can change that, and HMRC charges penalties from the first day a return is late.
By Andy Jackson, Head of Accountancy
Updated 26 October 2026
6 min read
Key takeaways
- You need a tax return if you have income or gains that PAYE does not collect, such as rental income, savings interest over £10,000, foreign income or capital gains to report.
- Register by 5 October after the end of the tax year. File online by 31 January.
- Tax is due by 31 January. Many people who file also make payments on account on 31 January and 31 July.
- A late return costs £100 straight away, with further penalties at three, six and twelve months.
Who needs to file
Employees and pensioners whose income is all taxed through PAYE usually do not need a return. HMRC expects one when some of your income or gains are not taxed at source. The common reasons for private clients are:
- rental income of more than £2,500 after expenses, or more than £10,000 before expenses;
- savings and investment interest of more than £10,000. Below that, HMRC usually collects the tax through your tax code;
- income from abroad;
- capital gains that must be reported, for example on shares, funds or a second home;
- the High Income Child Benefit Charge, which applies when you or your partner have adjusted net income over £60,000 and someone in the household claims Child Benefit. Employees and pensioners can now pay it through their PAYE tax code instead of filing a return;
- foreign income or gains, or a change in your residence status;
- acting as a trustee, or as the personal representative of an estate that has income.
If HMRC sends you a notice to file, you must file even if you think no tax is due. If you no longer need to file, ask HMRC to withdraw the notice rather than ignoring it.
The deadlines
The UK tax year runs from 6 April to 5 April. The deadlines after the end of each tax year are:
- 5 October: register for self assessment if you have not filed before.
- 31 October: file a paper return.
- 30 December: file online if you want tax of less than £3,000 collected through your PAYE tax code.
- 31 January: file online and pay any tax still due, plus the first payment on account for the current year.
- 31 July: the second payment on account.
For the 2025/26 tax year, the online filing and payment deadline is 31 January 2027.
Filing early does not bring the payment date forward. It does tell you the bill months in advance, which helps with cash flow and gives time to correct anything that looks wrong.
Talk to us about your position
Book a no-obligation consultation with the Totus One team.
Payments on account
If your last self assessment bill was £1,000 or more, and less than 80% of your total tax was collected at source, HMRC asks for advance payments towards the next year. Each payment on account is half of the previous year's bill, due on 31 January and 31 July. Any difference is settled the following 31 January.
The first year of a new source of income often brings a large January bill: the full tax for the year just ended, plus half of the same amount again as the first payment on account. If you expect your income to fall, you can apply to reduce your payments on account. Reducing them too far means interest on the shortfall.
Late filing and late payment
HMRC charges a £100 penalty as soon as a return is late, even if no tax is owed. After three months, daily penalties of £10 apply for up to 90 days. At six months and again at twelve months, a further penalty of 5% of the tax due or £300, whichever is higher, is added.
If your self-employment and property income together is more than £50,000 a year before expenses, Making Tax Digital for Income Tax has applied since 6 April 2026. You keep digital records, send quarterly updates through compatible software, and a points-based penalty system replaces the late filing penalties above. The threshold falls to £30,000 from April 2027 and £20,000 from April 2028.
Late payment brings interest from the due date and separate late payment penalties. If you cannot pay in full, contact HMRC before the deadline. A Time to Pay arrangement is usually available for people who ask early.
Records to keep
Keep the documents behind each figure on your return: P60s and P11Ds, bank and building society interest statements, dividend vouchers, investment platform tax packs, records of purchases and sales, and pension contribution statements. For personal income, keep records for at least 22 months after the end of the tax year. Keep them for five years after the 31 January filing date if you have property income.
A tax return shows where your money comes from each year. It is the starting point for pension contributions, the timing of capital gains and lifetime gifts.
Frequently asked questions
Do I need to file a tax return if all my income is taxed through PAYE?
Usually not. You may still need one if you have capital gains to report, rental or foreign income, savings interest over £10,000, or a High Income Child Benefit Charge that you do not pay through your tax code.
What is the deadline for an online tax return?
31 January following the end of the tax year. For 2025/26 that is 31 January 2027.
What happens if I file late?
There is an immediate £100 penalty, daily penalties after three months and further penalties at six and twelve months, plus interest on any tax paid late.
Can I reduce my payments on account?
Yes, if you expect your income to fall. If you reduce them too far, HMRC charges interest on the difference.
Sources & further reading
This article is general information, not advice. Tax, financial and legal rules change and their effect depends on your circumstances. Check the current position and take professional advice before acting. Last reviewed 26 October 2026. Totus One Limited (company no. 16855798).
Founder of Buzz Accounting, Practice Group and Founder Capital, Andy has built businesses across accountancy, fintech, private equity and e-commerce. He brings the discipline of a COO, the mindset of a founder and the connections of an investor — and a conviction that most businesses aren't broken, they're just leaking time and money.
The Totus One brief
One email a month on tax, wealth and law for private clients.
By subscribing you agree to our privacy notice.