HM Revenue and Customs (HMRC) has confirmed extra charges of up to £300 from August for UK households yet to file their Self Assessment tax returns. Anyone that failed to send their tax return to HMRC by the deadline of January 31 earlier this year will have already been given an automatic £100 fixed penalty, even if they had no tax to pay, or if any tax due was paid on time.
Daily penalties and the three-month period
But if you still haven't filed your tax return, the penalties are now even greater. Under HMRC rules, late filers face additional daily penalties of £10 per day for every day that a tax return is late, up to a maximum of £900. HMRC began rolling out these daily penalties to households from May 1 - three months after the initial January 31 submission deadline - for a period of 90 days, up to a maximum of £900.
This three month penalty period came to an end on July 31 meaning extra charges now apply from August for tax returns that are six months late, with HMRC charging a penalty of 5% of the tax due or £300, whichever is greater.
Further penalties at six and 12 months
Low Incomes Tax Report Group explains: "Late filing penalties increase significantly if a Self Assessment tax return is more than three months late, because HMRC can then charge a £10 penalty for each day that the return remains outstanding. This means that daily penalties for 2024/25 tax returns will normally start to be charged from 1 May 2026. The penalties will continue for up to a maximum of 90 days if you don’t file the return – so total daily penalties could reach £900."
Further late filing penalties can apply at 6 months and 12 months late (in most cases the relevant dates are 31 July 2026 and 31 January 2027 respectively) – each of these penalties will usually be the higher of £300 and 5% of the tax liability. After 12 months, so from January 31, 2027 onwards, late filers will be hit with another 5% or £300 charge, again whichever is the greatest.
Late payment penalties and interest
Additionally, if you pay your tax late, you’ll also get penalties of 5% of the tax unpaid at 30 days, six months and 12 months. If tax remains unpaid after the deadline, interest will also be charged on the amount owed in addition to the penalties above.
Confirming the penalties for late self assessment tax returns, HMRC said: “If you send your tax return late you’ll get the following late filing penalties: 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. To avoid this, send your Self Assessment tax return as soon as possible. All partners will be charged a penalty if a partnership tax return is late. If you pay your tax late you’ll get penalties of 5% of the tax unpaid at 30 days, 6 months and 12 months. You’ll also be charged interest on the amount owed. To avoid this, pay your Self Assessment tax bill as soon as possible."
HMRC says penalties must be paid within 30 days of the date on the penalty notice and you'll be charged interest if you pay after the deadline. If the payment deadline falls on a weekend or Bank Holiday, make sure your payment reaches HMRC on the last working day before it, unless you’re paying by faster payments. You can pay your penalty through your online bank account, by bank transfer, direct debit, at your bank or building society, or via a cheque through the post.
Official advice to file as soon as possible
Speaking after the submission deadline in January, Myrtle Lloyd, HMRC’s Chief Customer Officer, said: “Thank you to the millions of people and agents who filed their Self Assessment tax return and paid any tax owed by 31 January. Anyone who missed the deadline should file their return as soon as possible, as penalties and late payment interest may be charged. HMRC digital channels are always the quickest and easiest way for people to sort their tax affairs. Search ‘Self Assessment’ on GOV.UK to find out more."
