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📅 Updated for 2026/27

UK Tax Deadlines 2026/27

Every key HMRC date with a live countdown — Self Assessment, Payments on Account, registration deadlines, and the penalties for missing them.

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Full deadline timeline

All HMRC dates in chronological order. Colour shows urgency: red = within 30 days, amber = within 90 days, green = further out.

⚠️ Late filing penalties

What HMRC charges if you miss the Self Assessment deadline — even if you owe no tax

1 day late
£100 fixed penalty — applies immediately, even if you owe no tax or are due a refund.
3 months late
£10 per day, up to a maximum of £900 (on top of the £100).
6 months late
A further £300 or 5% of the tax due — whichever is higher.
12 months late
Another £300 or 5% of tax due. In serious cases, up to 100% of the tax due.
Late payment
Interest charged from the due date, plus 5% of unpaid tax at 30 days, 6 months, and 12 months.

Common questions

Quick answers about UK tax deadlines.

When is the Self Assessment deadline for the 2025/26 tax year?
The online filing deadline is 31 January 2027. Paper returns must be filed earlier, by 31 October 2026. Any tax you owe for 2025/26 must also be paid by 31 January 2027.
When do I need to register for Self Assessment?
If you became self-employed or started receiving untaxed income during the 2025/26 tax year, you must register with HMRC by 5 October 2026. Registering late can lead to penalties if it results in late filing or payment.
What are Payments on Account?
If your Self Assessment bill is over £1,000, HMRC requires two advance payments toward next year's bill — each 50% of this year's tax. They're due 31 January and 31 July. Many first-time filers are caught out by effectively paying 150% of their tax bill in January.
What happens if I miss the deadline?
An immediate £100 penalty applies even if you owe nothing. Penalties escalate at 3, 6, and 12 months (see the table above). If you have a reasonable excuse — serious illness, bereavement, HMRC system failures — you can appeal.
When does the 2026/27 tax year start and end?
The UK tax year runs from 6 April 2026 to 5 April 2027. Income earned in this window is reported in the Self Assessment return due by 31 January 2028.

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Disclaimer: Dates shown are based on standard HMRC deadlines for the 2026/27 tax year and may change. This page is for general guidance only and is not financial or tax advice. Always confirm deadlines that apply to your circumstances on gov.uk or with a qualified accountant.