You need to file a Self Assessment tax return if you have income HMRC has not already taxed. This includes self-employed earnings over £1,000, rental income, large savings or dividend income, and foreign income. If PAYE covers all your salary or pension, you usually do not need to file.
This guide covers every situation that requires a return for the 2025/26 tax year. You must file this return online by 31 January 2027. We also explain what to do if you are not sure.
Quick Check: Do You Need to File?
| Your situation | Do you need to file? |
|---|---|
| Self-employed with gross income over £1,000 | Yes |
| Partner in a business partnership | Yes |
| Rental income of £2,500 or more after expenses, or £10,000 or more before expenses | Yes |
| Rental income between £1,000 and £2,500 | Contact HMRC, who may collect the tax through your tax code |
| Savings or investment income of £10,000 or more | Yes |
| Dividends of £10,000 or more | Yes |
| Income over £60,000 and you or your partner claim Child Benefit | Usually, unless you pay the charge through your tax code |
| Capital Gains Tax to pay | Usually, or use HMRC’s Capital Gains Tax service |
| Untaxed foreign income | Usually |
| Only a salary or pension through PAYE | Usually not |
Do Sole Traders Need to File a Tax Return?
Yes, if your gross self-employed income is more than £1,000 in the tax year. The trading allowance covers the first £1,000, so you do not need to report small side income below this level. The limit applies to your income before expenses, not your profit.
This includes side businesses such as online selling, freelance work and gig economy jobs. Since January 2024, online platforms report sellers’ income directly to HMRC. This makes unreported side income much easier for HMRC to spot. Sole traders report business income on the SA103 self-employment pages.
Partners in a business partnership must always file a return, whatever their share of the profit.
Do Landlords Need to File a Tax Return?
Most landlords do. You must file if your rental income is £2,500 or more after expenses. You must also file if it is £10,000 or more before expenses. Between £1,000 and £2,500, contact HMRC, who may collect the tax through your tax code. The property allowance covers income up to £1,000.
If you rent a furnished room in your own home, the Rent a Room Scheme gives you £7,500 a year tax-free. Our landlord accountants can check which allowance works better for you.
What About Savings, Investments and Dividends?
You must file if you receive £10,000 or more from savings or investments. The same applies to dividends of £10,000 or more. Below these levels, tell HMRC about any taxable amount, and they will usually adjust your tax code.
The dividend allowance is £500, so HMRC only taxes dividends above this amount. Directors who take a mix of salary and dividends often pass the £10,000 dividend level and need to file.
Do High Earners Need to File?
A high salary alone no longer means you must file. HMRC removed the old £150,000 filing rule from the 2023/24 tax year onwards.
However, if your income is over £60,000 and you or your partner claim Child Benefit, you owe the High Income Child Benefit Charge. Employed people can now pay this through their tax code using HMRC’s online service. Otherwise, you need to file a return. Your Personal Allowance also starts to reduce once your income passes £100,000. Our high earner tax planning service can help you manage this.
Do I Need to Report Capital Gains?
Did you sell shares, cryptoassets, a second property or other assets at a gain? If the gain is above the £3,000 annual exempt amount, you usually have Capital Gains Tax to pay. You can report it on your tax return or through HMRC’s separate Capital Gains Tax service.
UK residential property has its own rule. You must report and pay any tax due within 60 days of completion, even if you also file a Self Assessment return.
Other Reasons You May Need to File
- Foreign income: untaxed income from abroad, such as overseas rent or interest, usually needs a return.
- Other untaxed income: tips or commission of £2,500 or more that your employer did not tax through payroll.
- Employment expenses over £2,500: you must claim amounts above this level through Self Assessment.
- A notice from HMRC: if HMRC sends you a notice to file, you must file or ask HMRC to withdraw it. This applies even if you think you owe nothing.
Being a company director does not automatically mean you must file. However, directors with dividends of £10,000 or more, or other untaxed income, do need to. HMRC also often sends directors a notice to file.
Who Does Not Need to File?
You usually do not need to file if PAYE covers all your income, such as a salary, a second job or a workplace pension. Your employer normally taxes a second job using a BR tax code. HMRC can usually collect tax on small amounts of untaxed income through your tax code instead.
How Do I Register for Self Assessment?
If you need to file for the first time, register with HMRC by 5 October after the tax year ends. For 2025/26, that deadline was 5 October 2026. If you missed it, register as soon as possible, because HMRC may charge a penalty if you pay tax late.
Once you register, HMRC sends your Unique Taxpayer Reference (UTR), which you need to file. You must file your 2025/26 return online and pay any tax owed by 31 January 2027.
See all the Self Assessment deadlines for 2025/26.
What Changes With Making Tax Digital?
From April 2026, sole traders and landlords with qualifying income over £50,000 must keep digital records. They must also send quarterly updates to HMRC. The threshold falls to £30,000 from April 2027 and £20,000 from April 2028. Our Making Tax Digital guide explains who this affects and when.
Still Not Sure?
HMRC’s online tool lets you check if you need to send a Self Assessment tax return in a few minutes. Do you have more than one type of income? Our Self Assessment accountants in Slough can confirm whether you need to register. We can also prepare your return before the 31 January deadline.
Frequently Asked Questions
Do I need to file if I earned under £1,000 from self-employment?
No, not for that income alone, because the £1,000 trading allowance covers it. You may still choose to file to record a loss or pay voluntary National Insurance.
Do I need to file if I stopped trading during the year?
Yes. You must file a return for the tax year in which you stopped trading. Tell HMRC your self-employment has ended so they stop sending you notices.
What happens if I should have filed but didn’t?
HMRC charges a £100 penalty as soon as your return is late. Further penalties and interest build up the longer it stays late. If you missed previous years, telling HMRC voluntarily usually means lower penalties.