MISSED THE DEADLINE? FILE A LATE OR AMENDED TAX RETURN

How much is the penalty for a late tax return?

These are HMRC's late filing penalties. They apply even if you have no tax to pay.

Paying late is charged separately: 5% of the unpaid tax at 30 days, 6 months and 12 months, plus interest at Bank Rate plus 4%. HMRC has a penalty estimator.

Deadlines for 2025–26

• Paper return: 31 October 2026
• Online return: 31 January 2027
• Paying the tax you owe: 31 January 2027

If you registered for Self Assessment after 5 October, HMRC gives you 3 months from the date of its letter to file. Deadlines on GOV.UK.

Can I file a return for an earlier year?

Yes. DTax Filer lets you prepare and file returns for earlier tax years as well as 2025–26. By law you have 4 years from the end of a tax year to send its return, so the oldest year you can still send is 2022–23 (until 5 April 2027). Penalties for an earlier year keep growing until it's filed, so send it as soon as you can.

How do I amend a tax return?

You can correct a return up to 12 months after the 31 January deadline: until 31 January 2027 for 2024–25, and until 31 January 2028 for 2025–26. In DTax Filer you open the return you sent, change it and submit the amendment online. Amendments are included in the price. After the 12 months you write to HMRC, and you can claim back tax you overpaid (overpayment relief) up to 4 years after the end of the tax year.

If you had a reasonable excuse

HMRC may cancel a penalty if something outside your control stopped you filing on time: for example serious illness or a hospital stay, the death of a partner or close relative shortly before the deadline, or a failure of HMRC's online service. Not having the money, or not getting a reminder, doesn't count. See reasonable excuses. You usually have 30 days from the penalty notice to appeal.

How to file a late return with DTax Filer

1. Create a free account and choose the tax year you need to file.
2. Enter your income, including any supplementary pages such as employment, self-employment or property.
3. Check the tax calculation before you send anything.
4. Submit to HMRC online with your UTR and Government Gateway sign-in details. It costs £14.50 per tax return.

Questions

I missed the 31 January deadline. What should I do now?

File as soon as you can. HMRC charges a £100 penalty straight away, and from 3 months late it adds £10 a day for up to 90 days. Filing before then stops the daily penalties from starting.

Can I file a tax return for an earlier year online?

Yes. You can prepare and file earlier years in DTax Filer. By law you have 4 years from the end of the tax year to send a return, so 2022–23 returns can be sent until 5 April 2027.

How long do I have to amend my tax return?

12 months from the 31 January filing deadline. A 2024–25 return can be amended until 31 January 2027, and a 2025–26 return until 31 January 2028. After that you write to HMRC, and you can claim overpayment relief up to 4 years after the end of the tax year.

Can I appeal a late filing penalty?

Yes, if you had a reasonable excuse, such as serious illness, a bereavement shortly before the deadline, or an HMRC online service failure. You usually have 30 days from the date of the penalty notice to appeal, and you still need to file as soon as you can.

Does a late return mean I pay interest?

Interest is charged on tax paid late, not on the return itself. HMRC's late payment interest is Bank Rate plus 4%, and there are separate late payment penalties of 5% of the unpaid tax at 30 days, 6 months and 12 months.

How much does it cost to file a late return with DTax Filer?

The same as any other return: £14.50 per tax return to submit to HMRC. You can prepare it free first, and amendments are included.