Do I need to file a Self Assessment this year?

You need to file if any of these applied to you in 2025/26

• You were self-employed and your turnover was more than £1,000 before expenses. Under £1,000 the trading allowance covers it and no return is needed for that alone.
• You let out property and the rent was more than £1,000 before expenses. The same £1,000 property allowance applies.
• You were a partner in a business partnership.
• Your total income was more than £150,000.
• You or your partner received Child Benefit and one of you had income over £60,000. The High Income Child Benefit Charge is collected through a return, unless you have chosen to have it taken through PAYE from 2025/26.
• You had untaxed income HMRC does not already know about: tips, commission, savings interest over your allowance, dividends over £500, or foreign income.
• You sold something that made a capital gain over £3,000, such as a second property or shares outside an ISA.
• HMRC has written to you asking for a return. If they ask, you file, even if nothing is due.

Things that do not, on their own, mean a return

• A salary on PAYE, even a large one under £150,000, as long as nothing else on the list applies.
• Savings interest inside your personal savings allowance: £1,000 for basic rate taxpayers, £500 for higher rate.
• Selling personal belongings for less than £6,000 each.
• A one-off sale on eBay or Vinted of things you owned. Trading, buying to sell on, is different and counts towards the £1,000 above.
• Your main home when you sell it, in almost every case.

If the answer is yes and you have never filed before

You register with HMRC first, and the deadline for that was 5 October 2026 for the 2025/26 year. If you have missed it, register now anyway. HMRC rarely penalises a late registration when the return and the tax arrive on time.

Registering gets you a Unique Taxpayer Reference, a ten-digit number that arrives by post in about ten days. You need it to file, so it is the one step that cannot be left to January.

The dates

• 31 October 2026: paper returns.
• 30 December 2026: online returns, if you want tax under £3,000 collected through your PAYE code rather than paid in one go.
• 31 January 2027: online returns, and the day the tax is due.

If you are still not sure

The wizard below asks eight questions and gives a yes, a no, or a yes with the reason. It keeps nothing you type.