Do I need to do a self assessment tax return?

You need to do a self assessment tax return if, in the last tax year, you were self-employed and earned more than £1,000, were a partner in a business partnership, had capital gains tax to pay, or had to pay the High Income Child Benefit Charge outside PAYE, among other reasons GOV.UK lists. Untaxed income such as rent, tips or foreign income can also mean you need one. If your only income is a salary or pension taxed at source, you often will not, but the safest answer comes from GOV.UK's own checker.

The situations GOV.UK lists

GOV.UK sets out when you must send a tax return. You need one if any of these applied in the last tax year:

you were self-employed as a sole trader and earned more than £1,000, before taking off anything you can claim tax relief on
you were a partner in a business partnership
you had to pay capital gains tax when you sold or disposed of something that increased in value
you had to pay the High Income Child Benefit Charge and do not pay it through PAYE
you are an off-payroll worker who is repaying a student or postgraduate loan

The £1,000 figure for self-employment is measured before expenses. Someone who earned a little over £1,000 from a craft stall and spent most of it on materials still crosses the line, even though their profit is small.

Untaxed income can also mean a return

Beyond that list, GOV.UK says you may need to send a return if you have any untaxed income. Its examples are money from renting out property or land, tips and commission, savings interest, dividends including from investments, foreign income, and any taxable UK income if you are not a UK resident.

For property, GOV.UK's allowances guidance is more specific: gross property income of £1,000 or less does not need to be reported, income over £1,000 up to £2,500 means contacting HMRC, and property income over £2,500 requires you to register for self assessment. Savings interest and dividends are often covered by their own allowances, which our guide to income tax rates and bands sets out.

When a small side income does not count

The trading allowance and property allowance are each a tax exemption of up to £1,000 a year. If your trading income is £1,000 or less, GOV.UK says you do not need to tell HMRC about it, unless you cannot use the allowance for another reason or must register anyway. The same applies to property income under the property allowance. You still need to keep records of the income.

The allowance cannot be used for income from your employer, or your spouse's or civil partner's employer, or from a company or partnership that you or someone connected to you owns or controls. Our guide to the £1,000 trading allowance covers the detail.

The government announced on 28 October 2026 that the trading allowance will rise from £1,000 to £3,000 from 6 April 2027, with the self assessment reporting threshold for trading income rising too. That change is announced but not yet law, as it needs the Finance Bill 2026-27.

Selling things and capital gains

Clearing out a loft is not the same as running a business. HMRC's guidance on selling online says you are unlikely to pay tax if you sell personal items from your home, and that you probably do not have to pay income tax on personal possessions. It adds that if you sell an item for more than £6,000, you may need to pay capital gains tax.

Property is the case that most often surprises people. If you sell a UK residential property that is not your home and capital gains tax is due, GOV.UK says you must report and pay within 60 days of completion, separately from the annual return. The annual exempt amount for individuals is £3,000 for 2026 to 2027.

If you are still not sure

GOV.UK's check if you need to send a tax return tool asks a series of questions and gives a personal answer, and it is worth running through before you register or decide not to. If it says you need to file and you have not done so before, you must tell HMRC by 5 October after the end of the tax year; our guide on how to register for self assessment explains the steps.

None of this is tax advice, only general information. If your income is mixed or you would rather someone looked at it properly, our self assessment tax returns page explains how an accountant can help. We read every enquiry sent through get in touch and, where we can, we will put you in touch with a local accountant.

Common questions

Do I need a tax return if I only have a job?

Usually not, if all your income is taxed through PAYE and nothing on GOV.UK's list applies, such as capital gains tax to pay or the High Income Child Benefit Charge outside PAYE. GOV.UK's online checker will confirm it for your circumstances.

Do I need to declare money from selling things online?

Selling your own unwanted belongings is unlikely to be taxed, according to HMRC. Buying or making goods to sell at a profit is likely to be trading, and if that income goes over £1,000 in a tax year you need to tell HMRC.

Do I need a tax return for a small amount of rental income?

It depends on the amount. Gross property income of £1,000 or less is covered by the property allowance, income over £1,000 up to £2,500 means contacting HMRC, and over £2,500 you register for self assessment. Letting a room in your own home has its own rules, so run GOV.UK's checker if that is your situation.

What if I should have filed in earlier years?

Tell HMRC as soon as you can. GOV.UK's deadlines page notes that the deadline for earlier returns has passed, and its penalties page says the failure to notify penalty is based on the amount still left to pay, so settling the tax quickly keeps it down.

Sources for the figures on this page

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