Do I need to fill in a self assessment tax return?
The situations that trigger a return, the ones that only look like they do, and the checker that answers it definitively in two minutes.
- Difficulty
- beginner
- Time
- 15 min
- Read
- 3 min
Short answer
You generally need a return if you were self-employed above the trading threshold, a partner in a partnership, a company director with untaxed income, receiving rental income above the property allowance, receiving significant untaxed income, liable to the High Income Child Benefit Charge, or you have capital gains to report. HMRC's own online checker settles it. If HMRC has sent you a notice to file, you must file, even if you owe nothing.
Two things trip people up. The first is that a notice to file creates the obligation regardless of whether any tax is due — ignoring it produces penalties for a nil return. The second is the opposite error: assuming that having a side income automatically means a return, when small amounts within the trading allowance often do not.
Step by step
- Check whether HMRC has issued a notice to file.Look in your HMRC online account and your post. A notice creates a legal obligation to file by the deadline whether or not you owe tax. If you believe it was issued in error, ask HMRC to withdraw it — do not simply not file.
- Run HMRC's online checker.GOV.UK has a short tool that asks about your circumstances and gives a definitive answer. It is quicker and more reliable than working through the criteria yourself, and it reflects the current thresholds.
- Consider self-employment and side income.Trading income above the trading allowance requires a return. Below it, in most cases, it does not — but the allowance is per person across all trading income, not per activity. See the guide on tax on selling things online for where the line falls.
- Consider property income.Rental income above the property allowance requires a return. There is a separate scheme for renting a room in your own home with its own, higher threshold and its own election.
- Consider untaxed income and investment income.Interest and dividends above the relevant allowances, income from abroad, and income where tax has not already been deducted. Small amounts of savings interest can often be collected through your tax code instead of a return.
- Consider the High Income Child Benefit Charge.If you or a partner receive Child Benefit and either of you has adjusted net income above the threshold, the charge applies and has historically been collected through a return. There is now also a PAYE route for some people. See the dedicated guide.
- Consider capital gains.Disposing of assets above the annual exempt amount, and particularly property, has separate and much shorter reporting deadlines than the annual return.
- Note the deadlines once you know you must file.The tax year ends 5 April. Paper returns are due by the following 31 October; online returns and payment of the balance by 31 January. Registering for the first time has its own earlier deadline of 5 October after the end of the tax year.
- Tell HMRC when you no longer need to file.The obligation does not lapse by itself. If your circumstances have changed, ask HMRC to remove you from self assessment, or returns and penalties keep arriving.
Common mistakes
- Ignoring a notice to file because no tax is due — Penalties for late filing are charged on the failure to file, not on the tax owed. A nil return filed late still attracts them.
- Assuming a first return is due the same year the income starts — The registration deadline is 5 October after the end of the tax year, and the return itself the following 31 January. That is a long gap, and it is why people forget.
Questions people ask
Do I need a tax return if I am employed and pay PAYE?
Usually not, unless you have other income or circumstances that trigger it — high income with Child Benefit, significant untaxed income, or a notice from HMRC. Most employees never file.
What happens if I file late?
An automatic fixed penalty applies from the day after the deadline, with further penalties and interest as time passes. HMRC will cancel penalties where there is a reasonable excuse, but you have to ask.
Can I stop filing once I have started?
Yes, but you must tell HMRC that the circumstances no longer apply and ask to be taken out of self assessment. Until they confirm, the obligation continues.