HMRC late filing penalty: what it means
An HMRC late filing penalty is a charge because your Self Assessment tax return was not filed by the deadline. It starts at a fixed £100 even if you owe no tax, and grows the longer the return is outstanding — but you can appeal if you had a reasonable excuse.
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An HMRC late filing penalty is a charge because your Self Assessment tax return was not filed by the deadline. It starts at a fixed £100 even if you owe no tax, and grows the longer the return is outstanding — but you can appeal if you had a reasonable excuse.
Last reviewed: July 2026 · Written in plain English, checked against gov.uk · Information only, not legal advice
Self Assessment late filing penalty: the essentials
- Initial penalty£100 fixed (even if no tax is due)
- After 3 months£10 per day, up to £900
- After 6 monthsA further 5% of tax due, or £300 if greater
- After 12 monthsAnother 5% or £300, whichever is greater
- Appeal window30 days from the penalty notice
How much are HMRC late filing penalties?
The penalties for a late Self Assessment return build up in stages. You get an automatic £100 penalty as soon as the return is late, even if you have no tax to pay or have already paid. After three months, daily penalties of £10 start, up to a maximum of £900. After six months there is a further penalty of 5% of the tax due or £300 (whichever is greater), and the same again after twelve months. Late payment of the tax itself carries separate charges.
What is the difference between late filing and late payment penalties?
Late filing penalties are for sending the return in late; late payment penalties are for paying the tax late. They are separate and can both apply. On the payment side, HMRC charges 5% of the unpaid tax at 30 days, again at 6 months, and again at 12 months, plus interest on the amount owed. Filing on time even if you cannot pay yet avoids the filing penalties and gives you a base to arrange payment.
Can I appeal an HMRC late filing penalty?
Yes. You can appeal within 30 days of the penalty notice if you have a 'reasonable excuse' — something that stopped you filing on time that a responsible person could not have foreseen, such as a serious illness, a bereavement, or a genuine service failure. You normally need to have filed the outstanding return first. You appeal online or using form SA370, explaining what happened and when. If HMRC accepts the excuse, the penalty is cancelled.
What happens if you ignore it?
Ignoring a late filing penalty lets it grow: daily penalties and further percentage charges stack up, and the debt is collected like any other tax debt, potentially through debt collectors or court action, with interest added. The two things that stop the bleeding are filing the outstanding return (which halts filing penalties from climbing further) and either paying or appealing. If you had a genuine reason for filing late, appealing within 30 days is well worth doing.
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See what your letter means — freeFrequently asked questions
Do I get a £100 penalty even if I owe no tax?
Yes. The initial £100 late filing penalty applies even if your tax bill is zero or already paid, because it is for the return being late, not the tax.
What counts as a reasonable excuse?
Examples HMRC accepts include serious illness, a close bereavement, or a documented HMRC service failure. Simply forgetting or finding the return difficult usually does not count.
How do I appeal?
File any outstanding return, then appeal online or with form SA370 within 30 days of the penalty notice, explaining your reasonable excuse.
Official sources & free help
For the full detail — and free, independent advice — see: