UK Tax Deadline Checker — Am I Late?

Online Self-Assessment returns and any balancing payment are due by 31 January following the end of the tax year. Paper returns must reach HMRC by the earlier 31 October deadline. Missing the deadline triggers an automatic £100 fixed penalty, plus daily and percentage penalties as time passes.

Since 1 January 2023, late VAT returns add a point to your VAT points record; financial penalties only apply once you hit the points threshold (4 for quarterly returns). Late payment carries a 2% penalty if 16–30 days late, 4% at day 31, then daily interest at 4% AER on the unpaid amount.

Your CT600 must be filed within 12 months of the end of the accounting period. The Corporation Tax itself is due earlier — 9 months and 1 day after the period end (or in quarterly instalments for very large companies). Missing the filing deadline triggers a £100 flat penalty, rising after three months.

P11D forms and the associated P11D(b) must be filed by 6 July following the end of the tax year. Class 1A NI on the benefits is payable by 22 July (or 19 July if paying by post). Late P11D(b) penalties are £100 per 50 employees per month.

There is no financial penalty for a late Confirmation Statement, but Companies House can start strike-off proceedings if you ignore it. Directors can also be criminally liable. Filing the CS01 is straightforward — Countify can take it over as part of your retainer.