2026/27 HMRC RatesFree
Personal Tax Penalty Calculator UK
Calculate HMRC penalties for late Self Assessment tax returns and late payment. Understand what you may owe if you miss the deadline.
Tax Penalty Calculator
Enter your tax details and how late you are
The amount of Self Assessment tax you owe
Days after 31 January deadline
Days after payment deadline
Penalty Calculation
Total Penalties
£450
Total Amount Owed
£5,512
| Original Tax Due | £5,000 |
| Late Filing Penalties | +£200 |
| Late Payment Penalties | +£250 |
| Interest Charges (7.5% p.a.) | +£62 |
| Total Amount Owed | £5,512 |
Filing Penalty Rates
1 day late£100
3 months late£10/day (max £900)
6 months late£300 or 5% tax
12 months late£300 or 5% tax
Payment Penalty Rates
30 days late5% of tax
6 months late+5% of tax
12 months late+5% of tax
Key Deadlines
Paper returns: 31 October
Online returns: 31 January
Payment deadline: 31 January
Payment on account: 31 July