Question 1

What is the Self Assessment late filing penalty in 2026?

Accepted Answer

For a standard Self Assessment return under the current late-filing regime, an initial £100 fixed penalty applies when the return is filed after its deadline. If the return remains outstanding after 3 months, daily penalties of £10 can be charged for up to 90 days. After 6 months, a further penalty is normally the greater of 5% of the tax liability or £300. A further penalty normally applies at 12 months, although higher penalties can apply where information was deliberately withheld.

Question 2

Does the £100 penalty apply if I have no tax to pay?

Accepted Answer

Yes. The initial £100 late-filing penalty can apply even if there is no tax to pay, or if the tax due has already been paid. The filing penalty is separate from penalties for paying tax late.

Question 3

How are the £10 daily Self Assessment penalties calculated?

Accepted Answer

Daily penalties can be charged when the return remains outstanding after 3 months. They are £10 per day for a maximum of 90 days. HMRC issues a notice specifying the date from which the daily penalties are charged, so a calculator should not assume that the daily charge automatically starts on exactly the day the three-month threshold is reached.

Question 4

What happens if my Self Assessment return is more than 6 or 12 months late?

Accepted Answer

At 6 months, a further penalty is normally the greater of 5% of the tax liability shown by the return or £300. At 12 months, another penalty normally uses the same 5% or £300 calculation. However, if HMRC considers that information was deliberately withheld, higher 12-month penalties can apply, including 70% or 100% of the relevant tax liability depending on the behaviour.

Question 5

Can I appeal a Self Assessment late filing penalty?

Accepted Answer

Yes. You can appeal if you have a reasonable excuse or otherwise believe the penalty is wrong. GOV.UK says you usually have 30 days from the date the penalty was issued to contact HMRC or appeal. Examples of circumstances that may amount to a reasonable excuse include serious illness, bereavement, certain HMRC online-service problems, computer or software failure and other events outside your reasonable control. You should file the return as soon as you are able.

Question 6

Are late filing penalties the same as late payment penalties?

Accepted Answer

No. Late filing penalties are charged because the return was submitted late. Late payment penalties arise separately when tax is paid late, and interest can also apply to unpaid tax. In addition, people using Making Tax Digital for Income Tax may be subject to the newer points-based late-submission and revised late-payment rules for the tax years to which those rules apply.

6-Month Penalty (Greater of 5% tax or £300)	£0
12-Month Penalty (Standard 5%)	£0

Time Overdue	Statutory Penalty Rule
1 Day Late	£100 fixed initial penalty (applies even if £0 tax is owed).
After 3 Months	£10 per day for up to 90 days (max £900).
After 6 Months	Greater of 5% of tax liability or £300.
After 12 Months	Greater of 5% of tax liability or £300 (up to 100% for deliberate concealment).

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