Late Filing Penalty Calculator UK
Estimate your HMRC Self Assessment penalties for a late return and late tax payment, including daily penalties, 6 and 12 month charges and interest.
Calculate Your HMRC Penalties
Enter your filing deadline, the date you filed (or today’s date if you still have not), and the tax you owe. The calculator works out late filing penalties, late payment penalties and interest for a Self Assessment tax return.
Self Assessment Penalty Calculator
See what a late return and late payment could cost.
How HMRC Penalties Stack Up
Key points about late filing and late payment
Filing and Paying Are Separate
You can face late filing penalties, late payment penalties and interest at the same time. Filing on time avoids the filing penalties even if you cannot pay yet.
The £100 Is Automatic
Miss the deadline by a single day and the £100 fixed penalty applies, even if you owe no tax at all.
Daily Charges Have a Cap
From 3 months late, £10 a day is added for up to 90 days, a maximum of £900. The daily amount stops growing once you file.
Act Early to Limit the Cost
Filing and paying as soon as possible stops further penalties and interest. If you cannot pay in full, contact HMRC about a payment plan.
Self Assessment Penalty Timeline
How penalties build up for a return and payment due on 31 January. Dates are approximate and shown for a standard 31 January deadline.
| Stage | Approximate Date | Late Filing Penalty | Late Payment Penalty |
|---|---|---|---|
| 1 day late | 1 February | £100 fixed penalty | Interest starts, no penalty yet |
| 30 days late | After 2 March | No further penalty | 5% of unpaid tax |
| 3 months late | From 1 May | £10 a day for up to 90 days (maximum £900) | Interest continues |
| 6 months late | After 31 July | Greater of £300 or 5% of tax due | Further 5% of unpaid tax |
| 12 months late | After 31 January next year | Greater of £300 or 5% of tax due | Further 5% of unpaid tax |
Late Filing Penalty FAQ
Answers to the most frequently asked questions about HMRC late filing and late payment penalties.
HMRC charges an automatic £100 penalty if you miss the filing deadline. If the return is more than 3 months late, a further £10 a day applies for up to 90 days (a maximum of £900). At 6 months and 12 months, HMRC adds a further penalty of 5% of the tax due or £300, whichever is higher.
Yes. The £100 late filing penalty applies even if your tax bill is zero or already paid, because it is a penalty for submitting the return late, not for paying late.
Late payment is charged separately. HMRC adds a penalty of 5% of the unpaid tax at 30 days, again at 6 months and again at 12 months, plus daily interest on the unpaid amount from the day after the due date until it is paid.
Interest is charged daily on unpaid tax at HMRC’s published late payment rate, which is linked to the Bank of England base rate. The calculator lets you enter the current rate, so check GOV.UK for the latest figure.
Yes. You can appeal if you had a reasonable excuse for filing late, such as a serious illness or a bereavement. You normally need to appeal within 30 days of the penalty notice, so act quickly and keep any evidence.