Guides › Appeal a Self Assessment Penalty: Reasonable Excuse

Appeal a Self Assessment Penalty: Reasonable Excuse

Short answer: according to GOV.UK, you usually have 30 days from the date the penalty was issued to contact HMRC or make an appeal; if you miss the deadline you need to give a reason. To appeal a Self Assessment late filing or late payment penalty you explain why, for example that you had a reasonable excuse, or that you think the penalty is wrong.

How to appeal

GOV.UK offers a tool to check how to appeal an individual or partnership penalty. You can make your appeal online, or download form SA370 or SA371 to appeal by post. GOV.UK's general penalty page says a signed letter with your name and reference (for example your UTR) can be used to appeal; for Self Assessment penalties its guidance points to the online tool or forms SA370/SA371, so use those first.

What you need before you start (GOV.UK)

• The date the penalty was issued.
• The date you filed your return (if you have).
• The date you paid your tax (if you have).
• Details of your reasonable excuse.

What may count as a reasonable excuse (GOV.UK examples)

A close relative's death shortly before the deadline; an unexpected hospital stay; a serious or life-threatening illness; computer or software failure while preparing the online return; issues with HMRC's online services; fire, flood or theft; unpredictable postal delays; delays related to a disability or mental illness; being unaware of or misunderstanding your legal obligation; relying on someone else who did not send the return. You must send the return or payment as soon as you are able to.

What GOV.UK says will not count

A bounced cheque or failed payment because of lack of money; finding HMRC's online system too difficult; not getting a reminder; making a mistake on the return.

Pay or not while appealing?

GOV.UK says that if HMRC agrees your appeal, it repays what you paid with interest from the date you paid it, if you have no other outstanding tax to pay. Whether to pay the penalty while you wait is a decision to take with HMRC or an adviser; this page does not advise on it.

If you do not need to submit a return

GOV.UK says you can ask HMRC to cancel a penalty if you do not need to send a Self Assessment return. See stopping self-employment.

After the decision

If HMRC does not change its decision, GOV.UK says HMRC offers a review. You can also ask for a review at any time after you appeal, or take your appeal to the tax tribunal; if you asked for a review, wait for its outcome first. GOV.UK gives no 30-day limit for this step for Self Assessment penalties (a 30-day limit it states for indirect tax penalties, including VAT, does not apply here).

Related

Penalty amounts for missing 31 January; cannot pay.

Example (made-up numbers)

A freelancer was in hospital for the week before 31 January 2027 and filed three days late. She appeals within 30 days of the penalty notice date and explains the dates.

What we could not verify

• The outcome of any individual appeal: HMRC decides each case on its facts, so no result is implied.
• Details of the review and tribunal process (only outlined from GOV.UK).
• Any extra days for the post: GOV.UK tells you to appeal within 30 days of the date on the penalty notice, and this page promises no longer period. If you miss it, GOV.UK says to give a reason.

Sources (official)

• GOV.UK, Appeal a Self Assessment penalty for late filing or late payment — https://www.gov.uk/guidance/check-when-to-appeal-a-self-assessment-penalty-for-late-filing-or-late-payment (read in full, 17 October 2026)
• GOV.UK, Disagree with a penalty — https://www.gov.uk/tax-appeals/penalty (read in full, 17 October 2026)
• GOV.UK, Reasonable excuses — https://www.gov.uk/tax-appeals/reasonable-excuses (read in full, 17 October 2026)
• HMRC, SA370 Appeal form — https://assets.publishing.service.gov.uk/media/657af4f6095987001295e0d7/SA370__Appeal.pdf (extract read, 17 October 2026)

Deadlines calendar → Penalty estimator →

Not tax advice. See the disclosure.