Self Assessment: file online and pay your tax by 31 January

File your online tax return for the last tax year and pay the tax you owe by 11:59pm on 31 January. If you make payments on account, your first payment for the next year is due on the same day.

Deadline
Every year by 31 January
Last checked
Checked against the official source: 21 October 2026

What if you miss the deadline? A late return gets an initial £100 penalty, then £10 a day after 3 months (up to £900), and more after 6 and 12 months. Late payment adds 5% of the unpaid tax at 30 days, 6 months and 12 months, plus interest. You can appeal if you have a reasonable excuse.

31 January is the main Self Assessment deadline. By then you must file your online tax return for the tax year that ended the previous 5 April and pay any tax you owe. If you make payments on account, your first payment towards the next year's bill is also due.

How to do it

  1. Sign in to your HMRC online account and start your return for the last tax year. You can file from 6 April.
  2. Add your income from self-employment, property, employment and savings, and your allowable expenses.
  3. Submit the return and note the tax due, including any payment on account.
  4. Pay HMRC online, by bank transfer or by card. Allow time for the payment to arrive.
  5. If you want to pay through your tax code, file online by 30 December instead.

Common questions

What if 31 January falls on a weekend?

The deadline does not move. For payments, GOV.UK says to make sure your money reaches HMRC on the last working day before, unless you pay by Faster Payments or by debit or credit card.

What are the penalties for a late tax return?

£100 straight away. After 3 months, £10 a day up to £900. After 6 months and again after 12 months, 5% of the tax due or £300, whichever is greater.

Can I pay my tax bill in instalments?

Yes. You can set up weekly or monthly payments before the deadline with a budget payment plan.

Official source: gov.uk

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This information is not legal or tax advice.