Self Assessment deadline: 31 January 2027 for the 2025/26 tax year

Figures for England, Wales and Northern Ireland, checked against gov.uk on 27 October 2026. General information, not personal advice.

For the 2025/26 tax year (6 April 2025 to 5 April 2026), the online Self Assessment deadline is 31 January 2027. That's also when any tax you owe has to be paid. Here's everything around it.

The dates that matter

5 April 2026The 2025/26 tax year ended
5 October 2026Deadline to register for Self Assessment if you're new to it
31 October 2026Paper returns due
30 December 2026File online by now if you want tax under £3,000 collected through your tax code instead (if you're employed)
31 January 2027Online returns due, and any tax owed for 2025/26, plus your first payment on account for 2026/27 if one applies
31 July 2027Second payment on account for 2026/27

If you miss the deadline

Filing late: £100 straight away, even if you owe nothing. After 3 months, £10 a day for up to 90 days (£900). After 6 months, the greater of 5% of the tax due or £300, and the same again after 12 months.

Paying late: interest from the day after the deadline, plus a penalty of 5% of the unpaid tax at 30 days, 6 months and 12 months.

If you had a genuine reason, such as a serious illness, you can appeal. If you can't pay in full, HMRC can agree a payment plan; set it up before the deadline if you can.

Payments on account

If your Self Assessment bill was more than £1,000, and less than 80% of your tax was taken at source, HMRC asks for advance payments towards next year: half of this year's bill on 31 January and half on 31 July. So the first January can feel like paying 18 months at once. If you expect next year's bill to be lower, you can ask to reduce them.

If HMRC owes you money

A return isn't only about paying. If you claim reliefs, such as higher-rate pension relief or relief for days worked abroad, the return can produce a refund, usually within a few weeks of filing. You can claim back up to four years, so 2022/23 can still be claimed until 5 April 2027. See am I paying too much tax?

Worked any days outside the UK since you moved here?

If you moved to the UK in the last few years and travel for work, or work from home while visiting family, part of your pay may not be taxable in the UK. The free check tells you in two minutes whether it's worth claiming.

Do the free check

Common questions

When is the Self Assessment deadline for 2025/26?

31 January 2027 for online returns and for paying the tax you owe. Paper returns were due by 31 October 2026.

What is the penalty for a late tax return?

£100 straight away, even if you owe no tax. After 3 months, £10 a day for up to 90 days. After 6 months and again after 12 months, the greater of 5% of the tax due or £300.

What are payments on account?

Advance payments towards next year's bill, each half of this year's, due on 31 January and 31 July. They apply if your Self Assessment bill was over £1,000, unless at least 80% of your tax was already collected at source, for example through PAYE.

I haven't registered for Self Assessment yet. Is it too late?

Register now on gov.uk. The deadline to register was 5 October, but if you file and pay by 31 January you're usually not penalised for registering late.

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