Updated 15 October 2026 · For England, Wales and Northern Ireland
Self assessment deadlines: the key dates
| Date | What happens |
|---|---|
| 5 October | Register for self assessment if you became self-employed in the tax year that ended on 5 April. |
| 31 October | Deadline for paper tax returns. |
| 31 January | Deadline for online returns. Pay any balance for the last tax year and your first payment on account for this one. |
| 31 July | Second payment on account due. |
The tax year runs from 6 April to 5 April. So the return for the year ending 5 April 2026 is due online by 31 January 2027.
Payments on account explained
Payments on account are advance payments towards next year's tax bill. Each one is half of your last year's bill, and they're due on 31 January and 31 July.
You don't have to make them if your last bill was under £1,000, or if more than 80% of your tax was already taken through PAYE.
Why your first self assessment bill is so big
In your first year, the January payment covers two things at once: the whole bill for the year just finished, plus the first half of next year's bill in advance.
The best defence is to put money aside every month from day one, in a separate savings account.
How to pay your tax bill
Leave enough time for your payment to reach HMRC by the deadline:
- Same or next working day: online or telephone banking (Faster Payments), approving a payment through your bank in your HMRC online account, or a debit or corporate credit card online. HMRC doesn't accept personal credit cards.
- 3 working days: Bacs, or a Direct Debit you've already set up with HMRC.
- 5 working days: a Direct Debit you're setting up for the first time.
You can also pay in weekly or monthly instalments before the deadline, which spreads the cost and avoids a large January bill.
Can you reduce payments on account?
Yes. If your income is falling, you can ask HMRC to reduce them. Be careful: if you reduce them too far, HMRC charges interest on the shortfall. It's worth checking the figures with us first.
What if you're late?
- Filing late: for returns not yet under Making Tax Digital, there's an automatic £100 penalty if your return is up to 3 months late, and more after that.
- Paying late: HMRC charges interest from the due date, and further penalties if tax is still unpaid after 30 days, 6 months and 12 months.
- Can't pay? Contact HMRC before the deadline. You may be able to set up a Time to Pay arrangement and spread the cost.
If you've started using Making Tax Digital for Income Tax, different rules apply to late submissions. See our Making Tax Digital guide.
Common questions
When is the self assessment deadline for 2025/26?
The online tax return for 2025/26 is due by 31 January 2027. Paper returns were due by 31 October 2026. Any tax owed is also due on 31 January 2027.
When is the self assessment deadline for 2026/27?
The online return for 2026/27 is due by 31 January 2028. If you've joined Making Tax Digital, you file it through your MTD software.
What are payments on account?
Advance payments towards next year's tax bill, each half of last year's bill, due on 31 January and 31 July. They don't apply if your last bill was under £1,000, or if more than 80% of your tax was taken through PAYE.
When is my first self assessment deadline?
Register by 5 October after the end of the tax year you started working for yourself. Your first online return is then due by 31 January the following year.
Is there a self assessment deadline in July?
Yes. 31 July is when the second payment on account is due. There's no filing deadline in July.
How we can help
We prepare and file your return well before the deadline, tell you exactly what to pay and when, and remind you before every payment date. Book a free review call to get started.
Source: GOV.UK, Self Assessment tax returns: deadlines and Payments on account. General information only, not advice for your situation.