Self Assessment Deadlines: Dates Every Freelancer Needs
Self Assessment deadlines are fixed dates that repeat every year, yet they still catch out thousands of UK freelancers and sole traders. Miss one and penalties start immediately. This checklist sets out every key date, what each one means for you and a simple routine to stay ahead of them, with the dates worked out for the 2025/26 and 2026/27 tax years. It is general information, not tax advice; rules can change, so confirm dates and penalties on GOV.UK or with an accountant.
Key takeaways
- The tax year runs from 6 April to 5 April; every deadline relates to a tax year that has already ended.
- Register by 5 October, file a paper return by 31 October or an online return by 31 January.
- Tax is due by 31 January, and payments on account fall on 31 January and 31 July.
- A late return costs £100 straight away, even if you owe no tax, and penalties grow over time.
- Filing early does not mean paying early; it simply gives you time to plan.
Self Assessment works in arrears. You earn money during a tax year, and only after that year ends do you report it and pay the tax. That gap is useful, because it gives you months to prepare, but it also means the deadlines can feel far away until suddenly they are not.
Below is every date that matters for a typical sole trader, followed by a checklist you can copy into your own calendar.
The key Self Assessment dates at a glance
| Date | Deadline | Who it affects |
|---|---|---|
| 5 April | End of the tax year | Everyone: your records for the year are now complete |
| 6 April | New tax year begins; you can file the return for the year just ended | Everyone |
| 31 July | Second payment on account | People making payments on account |
| 5 October | Register for Self Assessment | New sole traders who started in the tax year just ended |
| 31 October | Paper return deadline | Anyone filing on paper |
| 31 January | Online return, balancing payment and first payment on account | Almost every Self Assessment taxpayer |
The dates for this year and next
Because each deadline relates to a tax year that has already ended, it helps to see them laid out by tax year. Here is how the dates fall for the two tax years most freelancers are dealing with right now.
2025/26 tax year (6 April 2025 to 5 April 2026)
- 5 October 2026: register if you started trading during 2025/26.
- 31 October 2026: paper return deadline.
- 31 January 2027: online return deadline, balancing payment for 2025/26 and first payment on account for 2026/27.
- 31 July 2027: second payment on account for 2026/27.
2026/27 tax year (6 April 2026 to 5 April 2027)
- From 6 April 2027: you can file your return.
- 5 October 2027: register if you started trading during 2026/27.
- 31 October 2027: paper return deadline.
- 31 January 2028: online return deadline, balancing payment for 2026/27 and first payment on account for 2027/28.
- 31 July 2028: second payment on account for 2027/28.
Pro tip
Set each reminder twice: once a month before the deadline and once a week before. The early reminder is the one that matters, because it leaves time to chase missing paperwork, sort out sign-in problems or move money into place.
Registration: 5 October
If you started working for yourself and earned more than £1,000 from self-employment in a tax year, you must register for Self Assessment by 5 October after the end of that tax year. You can start trading straight away and register later, but this is the latest date.
Registration is not instant. HMRC needs to set up your record and send your Unique Taxpayer Reference by post, and you need that before you can file. Registering soon after you start, rather than in October, avoids a rush before the January filing deadline. If you register late and do not pay your tax by 31 January, you can face a "failure to notify" penalty.
Filing: 31 October and 31 January
There are two filing deadlines, depending on how you file.
- Paper returns: must reach HMRC by 31 October after the end of the tax year.
- Online returns: must be submitted by 31 January after the end of the tax year.
Most freelancers file online, which gives you three extra months and an instant tax calculation. Filing online early, for example in the summer, does not bring forward your payment date. You still pay by 31 January, but you know the figure months in advance.
Common mistake
Leaving the online return until the last days of January. Sign-in problems, a lost password, a missing invoice or a bank statement you cannot download can all eat up time you do not have. Aim to file by the end of the year before, so January is only about paying.
Payments: 31 January and 31 July
The 31 January date is both a filing and a payment deadline. On that day you pay the balancing payment for the tax year just ended and, if they apply, your first payment on account for the current tax year.
How payments on account work
Payments on account are two advance payments toward your next tax bill, each normally half of the previous year's bill, including Class 4 National Insurance. They are due on 31 January and 31 July. You do not have to make them if your last bill was under £1,000, or if more than 80% of your tax was paid at source, such as through PAYE.
If your payments on account were too low, you pay the difference with the balancing payment the following 31 January. If you expect your profit to fall, you can apply to reduce them. Student loan repayments and capital gains are paid with the balancing payment, not through payments on account.
Example
Imagine Leo, a freelance developer whose Self Assessment bill for 2025/26 is £6,000 and who has no tax paid at source. On 31 January 2027 he pays the 2025/26 balancing payment plus a first payment on account for 2026/27 of £3,000. On 31 July 2027 he pays a second £3,000. When he files his 2026/27 return, any difference between the £6,000 he paid in advance and his actual bill is settled on 31 January 2028. The figures are made up to show how the timing works.
What happens if you miss a deadline
Penalties apply whether or not you owe any tax, so a late return can cost money even when your bill is zero.
Late filing penalties
- 1 day late: a £100 penalty.
- 3 months late: £10 a day, up to a maximum of £900.
- 6 months late: a further 5% of the tax due or £300, whichever is greater.
- 12 months late: another 5% of the tax due or £300, whichever is greater.
Late payment penalties
If you pay late, HMRC charges 5% of the unpaid tax at 30 days, at 6 months and again at 12 months, plus interest on the amount outstanding. Interest runs on late payments from the due date.
If something serious stopped you meeting a deadline, such as a serious illness or a bereavement, you can appeal a penalty on the basis of a "reasonable excuse". Do it promptly and keep evidence. If you cannot pay in full, contact HMRC early to discuss your options rather than waiting.
If you are within Making Tax Digital for Income Tax, late submissions are handled under a points-based system instead, which works differently from the penalties above.
A year-round routine to stay ahead
The best way to avoid deadline stress is to spread the work across the year. Here is a simple rhythm many freelancers use.
- April to June: close off the previous tax year's records, gather missing receipts and draft your return.
- July: pay your second payment on account if you make them, and check your tax savings are on track.
- September to October: file if you have not already. Register by 5 October if you started trading last tax year.
- November to December: confirm your January bill and move the money into place.
- January: pay by 31 January. Nothing else should be left.
If your qualifying income puts you within Making Tax Digital for Income Tax, from 6 April 2026 for those over £50,000, you also send quarterly updates through compatible software, so add those to your calendar too.
Your deadline checklist
- Add 5 October, 31 October, 31 January and 31 July to your calendar with early reminders
- Check you can sign in to your HMRC online account well before January
- Register by 5 October if you started trading in the last tax year
- File your online return before the end of the calendar year
- Check whether payments on account apply to you
- Keep tax savings in a separate account so payments are ready on time
- Contact HMRC early if you cannot pay in full
Frequently asked questions
Can I file my return before 5 April?
No. A return covers a complete tax year, so you can file from 6 April onward, once the tax year it covers has ended.
Does filing early mean I pay early?
No. Your payment is still due by 31 January, wherever in the year you file. Filing early simply tells you the amount sooner.
What if a deadline falls on a weekend?
Do not count on extra days. Treat the published date as the deadline and file and pay before it, allowing time for bank transfers to clear.
I missed 31 January. What should I do now?
File and pay as soon as you can, because daily penalties start after 3 months and interest builds on unpaid tax. If you had a reasonable excuse, appeal the penalty and explain what happened.
Related reading
The bottom line
Self Assessment deadlines are predictable: 5 October to register, 31 October for paper returns, 31 January to file online and pay, and 31 July for the second payment on account. Put them in your calendar once, file early and keep tax money set aside, and the penalties will never apply to you.
Dates, penalties and rates can change, so treat this as general information. Check the current guidance on GOV.UK or with HMRC, and ask an accountant if your situation is complicated.
