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Penalty notice · SA326D

HMRC penalty notice for Self Assessment (SA326D)

For a notice charging a Self Assessment penalty: for a tax return sent late (SA326D and the penalties that can follow it), for tax paid late, or for an inaccuracy. This page gives what GOV.UK and the law say, with each source and the date it was checked.

Last reviewed 8 October 2026 · How Tax Letters checks its facts

The short answer

What this letter is
GOV.UK says HMRC will send you a penalty notice if you miss the deadline for sending in your Self Assessment tax return or for paying your Self Assessment tax on time. GOV.UK says HMRC may charge you a penalty if you send a tax return late, pay your tax late, send an inaccurate return or fail to keep adequate records. [1] [2]
What it asks
GOV.UK says a Self Assessment penalty must be paid within 30 days of the date on the penalty notice, and that interest is charged if you pay after the deadline. [3]
Can it be appealed?
To challenge an HMRC tax decision or penalty you usually have 30 days from the date of the decision letter, or from the date the penalty was issued; the letter itself says how and by when. [4]
The dates
This page works out no dates. The ones that count are printed on your notice, and the next section says what each one means.
Your options at a glance
  • Appeals: usually 30 days from the notice date

Every fact on this page comes from a source listed at the foot of the page, with the date it was last checked. All sources and dates

The dates

Notice datedthe date printed on your noticeGOV.UK says a Self Assessment penalty must be paid within 30 days of the date on the penalty notice, and that interest is charged if you pay after the deadline.
Pay byas printed on your noticeThe date your notice gives for payment.
Time your notice givesin your notice's own wordsTo challenge an HMRC tax decision or penalty you usually have 30 days from the date of the decision letter, or from the date the penalty was issued; the letter itself says how and by when.
[3] [4]

No calendar date is worked out here for the appeal. The notice's own date and words are the ones that count.

If the notice is for an inaccuracy in a return

Notice datedthe date printed on your noticeUnder Schedule 24 to the Finance Act 2007, an inaccuracy penalty must be paid before the end of the period of 30 days beginning with the day on which notification of the penalty is issued.
[4] [5]

If the return or the tax is still late

GOV.UK lists these late filing penalties for a Self Assessment return:

  • an initial £100 penalty
  • after 3 months, additional daily penalties of £10 per day, up to a maximum of £900
  • after 6 months, a further penalty of 5% of the tax due or £300, whichever is greater
  • after 12 months, another 5% or £300 charge, whichever is greater
[6]

Under Schedule 55 to the Finance Act 2009, daily penalties apply only if the return is still not in after 3 months from the penalty date, HMRC decide that such a penalty should be payable, and HMRC give notice of the date from which it is payable. The penalty is £10 for each day the failure continues, for up to 90 days from that date. [7]

Under Schedule 55, the 6-month late filing penalty applies only if the return is still not in after the end of 6 months beginning with the penalty date. Schedule 55 defines the penalty date as the date a penalty is first payable for failing to make or deliver a return, that is to say, the day after the filing date. The 12-month penalty applies only if the return is still not in after the end of 12 months beginning with the penalty date. The law sets higher amounts where information is deliberately withheld. [8] [9] [10]

GOV.UK's calculator gives an estimate of the penalties and interest for a Self Assessment tax return sent late or a tax bill paid late. GOV.UK says it can only give an estimate, and that the amount HMRC asks for might be different. GOV.UK: estimate your penalty [11]

If the notice charges daily penalties

The notice gives the date daily penalties run from. Schedule 55 allows the date in HMRC's daily penalty notice to be earlier than the date the notice is given, but not earlier than the end of the 3 months. [7]

If the notice is for tax paid late

GOV.UK says that if you pay Self Assessment tax late you get penalties of 5% of the tax unpaid at 30 days, 6 months and 12 months, and you are also charged interest on the amount owed. [6]

If the notice is about a partnership return

GOV.UK says all partners will be charged a penalty if a partnership tax return is late. HMRC's Partnership Manual says that where a partnership return is late, the 6 and 12 month penalties are restricted to the statutory minimum of £300 in all cases, and are charged on each partner. [6] [12]

Appealing the penalty

For an individual or partnership Self Assessment penalty for late filing or late payment, GOV.UK's appeal tool lets you make your appeal online, or download form SA370 or SA371 to appeal by post. GOV.UK: appeal a Self Assessment penalty [1]

GOV.UK says that before you appeal you need the date the penalty was issued, the date you filed your return and the date you paid your tax if you have, and details of your reasonable excuse.

  • the date the penalty was issued
  • the date you filed your Self Assessment tax return, if you have sent it
  • the date you paid your tax, if you have paid it
  • details of your reasonable excuse for filing late or not paying on time
[1]

GOV.UK describes a reasonable excuse as something that stopped you meeting a tax obligation for a valid reason, and lists examples of what may count.

  • your partner or another close relative died shortly before the tax return or payment deadline
  • you had an unexpected stay in hospital that prevented you from dealing with your tax affairs
  • you had a serious or life-threatening illness
  • your computer or software failed while you were preparing your online return
  • issues with HMRC online services
  • a fire, flood or theft prevented you from completing your tax return
  • postal delays that you could not have predicted
  • delays related to a disability or mental illness you have
  • you were unaware of or misunderstood your legal obligation
  • you relied on someone else to send your return, and they did not
[13]

GOV.UK lists things that will not be accepted as a reasonable excuse.

  • your cheque bounced or payment failed because you did not have enough money
  • you found the HMRC online system too difficult to use
  • you did not get a reminder from HMRC
  • you made a mistake on your tax return
[13]

GOV.UK says that with a reasonable excuse the return or payment must still be sent as soon as you are able to. [13]

GOV.UK says that if you have appealed against a penalty, you will not have to pay it until your appeal has been settled. [14]

GOV.UK's Self Assessment appeal guidance suggests considering paying the penalty if you appeal: if you do not, and the appeal is rejected, you pay interest on the penalty from the date it was due to the date you paid it. If the appeal is agreed, HMRC repays what you paid with interest from the date you paid it, if you have no other tax outstanding. [1]

If HMRC does not change its decision or you cannot reach an agreement, GOV.UK says you will be offered a review, and you may also take your appeal to the tax tribunal. GOV.UK says a review is done by a review officer in a different team who was not involved in the original decision, and usually takes 45 days. If you disagree with the result, you can appeal to the tax tribunal, usually within 30 days of the date on the review result letter. [2] [15]

GOV.UK says that for a direct tax penalty you can also ask for a review at any time after you make an appeal, without waiting for the result, by writing to the HMRC office you sent the appeal to. [2]

HMRC's tool for checking when you can expect a reply covers queries and requests about Self Assessment, and GOV.UK says the information in it is updated weekly. GOV.UK: check when you can expect a reply from HMRC [16]

HMRC may send a text message if you appeal against a Self Assessment penalty, to confirm the appeal has been reviewed and when to expect the outcome. GOV.UK says these texts will not ask for personal or financial information or provide any links to websites. [17]

If the notice is about a partnership return

HMRC's Partnership Manual says an appeal against a penalty for sending a partnership return late may be brought only by the nominated partner (also called the representative or reporting partner) or their successor, and is treated as an appeal made on behalf of all the relevant partners. [12]

If the notice is for an inaccuracy in a return

For any other type of direct tax penalty, GOV.UK says to follow the instructions on the penalty letter or use the appeal form that came with it. [2]

HMRC's factsheet on penalties for inaccuracies (CC/FS7a) says HMRC will not charge a penalty for an inaccuracy if you took reasonable care to get things right but your return or document was still wrong. It gives keeping accurate records, and checking with a tax adviser or with HMRC if you are not sure about anything, as ways to show you took reasonable care. CC/FS7a sets out the 8 stages HMRC uses to work out a penalty for an inaccuracy, including its view of the behaviour, whether the disclosure was prompted or unprompted, and the reduction for the quality of disclosure, which it calls telling, helping and giving. GOV.UK: factsheet CC/FS7a, penalties for inaccuracies [18]

Paying it

Use the 11-character payment reference, a 10-digit number followed by the letter K, shown on your notice or in your HMRC online account. GOV.UK says that with the wrong reference “your payment may be delayed or used to pay a different tax bill that you owe”. [19]

GOV.UK lists the ways to pay a Self Assessment penalty: through your online or mobile bank account, by bank transfer (Faster Payments, CHAPS or Bacs), by Direct Debit, by debit or corporate credit card online, at your bank or building society, or by cheque through the post. A Self Assessment penalty cannot be paid by personal credit card. There is no fee for a personal debit card, and a fee that is not refundable for a corporate credit or debit card. GOV.UK: pay a Self Assessment penalty [3] [20]

If the notice is for tax paid late

On the Self Assessment tax itself, GOV.UK says: “If you’ve missed your Self Assessment payment deadline or you cannot pay the amount you owe, you might be able to set up a payment plan (also known as a ‘Time to Pay’ arrangement)”. Under Schedule 56 to the Finance Act 2009, if you ask HMRC to defer payment of tax you did not pay on time and HMRC agrees, you are not liable to a late payment penalty for that tax that would otherwise arise between your request and the end of the agreed period. If you break the agreement, HMRC can charge that penalty by notice. GOV.UK: pay your Self Assessment tax bill weekly or monthly [21] [22]

If the notice is for an inaccuracy in a return

HMRC's factsheet CC/FS7a says HMRC will write to tell you how much the penalty is and how it has worked it out. It then either sends a penalty assessment notice or invites you to enter into a contract to pay the penalty together with the tax and interest. GOV.UK's guide to paying taxes, penalties or enquiry settlements is for payments whose reference starts with X and that HMRC's other paying guides do not cover. If the reference does not start with an X, GOV.UK says to check HMRC's other paying guides. GOV.UK says paying through that guide needs your 14 or 15 character payment reference that begins with X, found on your payslip or Notice to Pay, and to contact HMRC if you are unsure about your payment reference. GOV.UK says that with an incorrect reference “there will be a delay in the payment being allocated correctly”. CC/FS7a says that in certain circumstances you may also have to pay interest on the penalty if you do not pay it on time. GOV.UK: pay taxes, penalties or enquiry settlements [18] [23]

If one of these is you

You did not need to send a return

GOV.UK says you can ask HMRC to cancel a penalty if you do not need to send a Self Assessment tax return. GOV.UK says to tell HMRC as soon as possible if you believe you no longer need to send a tax return, online or by phone or post, and that you may have to pay a penalty if you do not tell them early enough. [1] [24]

Your computer or HMRC's online service failed

If you could not file or pay because of computer problems, GOV.UK says an appeal should include the date you tried to file or pay online and details of any system error message. [2]

The time to appeal has passed

GOV.UK says you usually have 30 days from the date your penalty was issued to contact HMRC or make an appeal, and that if you miss the deadline you will need to give a reason. [2]

Your health or circumstances make this hard

HMRC offers extra support if your health condition or personal circumstances make it difficult to contact HMRC, for example a mental health condition, financial hardship or being treated in hospital. You can authorise a friend, relative or voluntary organisation to talk to HMRC for you and help you fill in forms. [25] [26]

If the notice is for an inaccuracy in a return

Your notice says the inaccuracy was careless

CC/FS7a gives the penalty range for a careless inaccuracy as 0% to 30% where the disclosure was unprompted, which means you told HMRC before you had any reason to believe it had found the inaccuracy or was about to. Where the disclosure was prompted, which means at any other time, CC/FS7a gives the range for a careless inaccuracy as 15% to 30%. The penalty is a percentage of what HMRC calls the potential lost revenue, the amount that arises from correcting the inaccuracy. HMRC's Compliance Handbook says the majority of inaccuracy penalties are calculated using the standard maximum penalty rates, and that higher maximum penalties may apply when offshore matters are involved. CC/FS7a says HMRC can suspend a penalty for a careless inaccuracy, for up to 2 years, if it can set conditions to help you avoid penalties in the future and believes you can meet them. If you meet the conditions you will not have to pay it, unless you become liable to another inaccuracy penalty during the suspension period. HMRC cannot suspend penalties for any other type of behaviour. [18] [27]

Your health or circumstances make this hard

CC/FS7a says that if anything about your health or personal circumstances made it difficult for you to take reasonable care, you can tell the officer dealing with the check, so they can take it into account when considering whether you took reasonable care. HMRC offers extra support if your health condition or personal circumstances make it difficult to contact HMRC, for example a mental health condition, financial hardship or being treated in hospital. [18] [25]

Someone helps you with your tax

You can authorise a friend, relative or voluntary organisation to talk to HMRC for you and help you fill in forms. You can also authorise an agent, such as an accountant or tax adviser, to deal with HMRC for you. [26]

Keep it and get help

Keep this with the notice. Mark what you did:

Appealed on ____________ online or by postPaid on ____________Sent the return on ____________

Need help with this?

Vision Consulting Chartered Accountants and Registered Auditors, Tax Letters' founding partner, is regulated by ICAEW. Talk to them in confidence, with no obligation. [28] [29] [30]

Call 020 8554 2135How Vision handles HMRC penalty appeals

You can also deal with HMRC directly, free, without any adviser. Free help: TaxAid, which says it helps “people who can’t afford to pay for help”, and Citizens Advice.

The two are connected. Tax Letters takes no referral fees.How Tax Letters is funded.

You can always deal with HMRC directly, free, without any service or adviser. HMRC's Self Assessment general enquiries line is 0300 200 3310, open Monday to Friday, 8am to 6pm, and closed on bank holidays. Free help: TaxAid, which says it helps “people who can’t afford to pay for help”, and Citizens Advice. [29] [30] [31]

If the notice is for an inaccuracy in a return

Keep this with the notice. Mark what you did:

Appealed on ____________ online or by postPaid on ____________

You can always deal with HMRC directly, free, without any service or adviser. Free help: TaxAid, which says it helps “people who can’t afford to pay for help”, and Citizens Advice. [29] [30]

Sources

Each source is linked, with the date Tax Letters last checked it.

  1. GOV.UK: Appeal a Self Assessment penalty for late filing or late payment (checked 7 Oct 2026)
  2. GOV.UK: Disagree with a tax decision or penalty, disagree with a penalty (checked 7 Oct 2026)
  3. GOV.UK: Pay a Self Assessment penalty (checked 7 Oct 2026)
  4. GOV.UK, Disagree with a tax decision or penalty (checked 8 Oct 2026)
  5. legislation.gov.uk: Finance Act 2007, Schedule 24, paragraph 13 (checked 7 Oct 2026)
  6. GOV.UK: Self Assessment tax returns, penalties (checked 7 Oct 2026)
  7. legislation.gov.uk: Finance Act 2009, Schedule 55, paragraph 4 (checked 7 Oct 2026)
  8. legislation.gov.uk: Finance Act 2009, Schedule 55, paragraph 5 (checked 7 Oct 2026)
  9. legislation.gov.uk: Finance Act 2009, Schedule 55, paragraph 1 (checked 7 Oct 2026)
  10. legislation.gov.uk: Finance Act 2009, Schedule 55, paragraph 6 (checked 7 Oct 2026)
  11. GOV.UK: Estimate your penalty for late Self Assessment tax returns and payments (checked 8 Oct 2026)
  12. HMRC Partnership Manual: PM148000, late filing penalties (checked 8 Oct 2026)
  13. GOV.UK: Disagree with a tax decision or penalty, reasonable excuses (checked 7 Oct 2026)
  14. GOV.UK: Disagree with a tax decision or penalty, delay payment during appeals and reviews (checked 7 Oct 2026)
  15. GOV.UK: Disagree with a tax decision or penalty, get a review (checked 8 Oct 2026)
  16. GOV.UK: Check when you can expect a reply from HMRC (checked 8 Oct 2026)
  17. GOV.UK: Check if a text message you've received from HMRC is genuine (checked 7 Oct 2026)
  18. GOV.UK: Compliance checks factsheet CC/FS7a, penalties for inaccuracies in returns and documents (checked 8 Oct 2026)
  19. GOV.UK: Pay a Self Assessment penalty, make a bank transfer (checked 7 Oct 2026)
  20. GOV.UK: Pay a Self Assessment penalty, by debit or corporate credit card online (checked 7 Oct 2026)
  21. GOV.UK: Pay your Self Assessment tax bill, pay weekly or monthly (checked 8 Oct 2026)
  22. legislation.gov.uk: Finance Act 2009, Schedule 56, paragraph 10 (checked 8 Oct 2026)
  23. GOV.UK: Pay taxes, penalties or enquiry settlements (checked 8 Oct 2026)
  24. GOV.UK: Self Assessment tax returns, if you no longer need to send a tax return (checked 7 Oct 2026)
  25. GOV.UK: Get help from HMRC if you need extra support (checked 7 Oct 2026)
  26. GOV.UK: Appoint someone to deal with HMRC on your behalf (checked 7 Oct 2026)
  27. HMRC Compliance Handbook: CH82120, penalties for inaccuracies, amount of penalty (checked 8 Oct 2026)
  28. Vision Consulting: Contact us (checked 7 Oct 2026)
  29. TaxAid: About us (checked 8 Oct 2026)
  30. Citizens Advice: About us (checked 7 Oct 2026)
  31. GOV.UK: Self Assessment: general enquiries (checked 7 Oct 2026)