Late filing penalty calculator

Free LetSentry tool. The full result is shown on the page — no account, email address or payment required.

FAQ

What are HMRC's Self Assessment late-filing penalties? £100 immediately after the deadline, £10/day after 3 months (up to £900), and the greater of £300 or 5% of tax due at 6 and 12 months. See gov.uk/self-assessment-tax-returns/penalties.

Are late-payment penalties separate? Yes. Late-payment penalties of 5% at 30 days, 6 months and 12 months apply on top of interest. See gov.uk/self-assessment-tax-returns/penalties-for-late-payment.