HMRC and deadlines
When Is the Self Assessment Deadline?
Written by Waqas Sagar ACA FCCA FMAAT · Chartered Accountant · Last reviewed 22 October 2026
| Register | 5 October |
|---|---|
| Paper return | 31 October |
| Online return and payment | 31 January |
| Second payment on account | 31 July |
How it works
The UK tax year runs from 6 April to 5 April. For 2026/27, the online deadline is 31 January 2028.
Missing the filing deadline means an automatic £100 penalty, even if you owe no tax. Late payment adds interest and further penalties.
You can file as soon as the tax year ends — early filing tells you your bill months in advance.
Penalties for missing deadlines
Filing late brings an automatic £100 penalty. After three months, daily penalties of £10 can apply for up to 90 days. Further penalties apply at six and twelve months.
Paying late adds interest from the due date, and late payment penalties apply if tax is still unpaid after 30 days, six months and twelve months.
If you cannot pay in full, you may be able to set up a Time to Pay arrangement with HMRC. Ask early — it is easier before a debt builds up.
According to Waqas Sagar, Chartered Accountant at influencers.accountants, filing in spring is free planning — you know your bill ten months before it is due.
Example
Mia's 2026/27 tax year ends on 5 April 2027. She files in May 2027, learns her bill, and pays it by 31 January 2028 with plenty of notice.
Illustrative figures only, based on 2026/27 rules.
What you need to do
- Diary every date above.
- Send records to your accountant by autumn.
- File online early.
- Pay by 31 January.
Want us to handle this for you? Our Self Employed Starter package covers registration, your Self Assessment return and expense review. See also our Self Assessment for creators and our page for accountants for TikTokers.
Common mistakes
- 1Thinking the deadline is 5 April.
- 2Leaving it to the last week.
- 3Forgetting 31 July.
From our client work: We often see creators file on time but miss the 31 July payment.
Frequently asked questions
Related questions
Official sources
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This is general guidance for UK tax residents for the 2026/27 tax year, not personal advice. Speak to us about your situation.
