HMRC SA316 notice to file explained
HMRC wants a Self Assessment tax return from you. Once you've had this notice, missing the deadline means an automatic fine, even if you owe no tax.
Last checked: 18 October 2026 · Written by Ivan S., finance professional
What this letter means
HMRC thinks you have income it needs to hear about: self-employment, rent, foreign income, or earnings over certain limits. The notice makes filing a legal duty for that tax year. The deadlines on the letter apply to the tax year ending the previous 5 April.
What happens if you're late
- 1 day late: £100 automatic penalty.
- 3 months late: £10 a day for up to 90 days (up to £900).
- 6 months late: a further £300 or 5% of the tax due, whichever is higher.
- 12 months late: another £300 or 5%, and possibly more.
Interest is also charged on any tax paid after 31 January.
What to do
- Register for online filing early. HMRC posts an activation code, which can take a while to arrive.
- Gather your records: P60, income and expenses from any side business, rent received, savings interest.
- File and pay by 31 January. The tax bill and the return share the same deadline.
Don't think you need to file?
Contact HMRC and ask them to withdraw the notice. They'll only do this if you have nothing extra to report, for example all your income was taxed through your wages. Don't just ignore it: the £100 penalty applies once a notice is issued.
Not sure if this is meant for you?
Upload your notice and we'll explain why HMRC likely sent it and draft a withdrawal request if you don't need to file.
Explain my letterThis is general information, not tax advice. Letter Sorted is independent and not affiliated with HMRC.