Understanding HMRC Self-Assessment Milestones
Missing an HMRC tax deadline can result in automatic penalties and escalating interest charges. Here is your definitive guide to staying on top of statutory filing dates.
Statutory Deadlines
- 5 October: Deadline to register for Self-Assessment if you became self-employed or received untaxed income.
- 31 October: Deadline for paper SA100 submissions.
- 31 January: Deadline for online filing, paying your balancing tax bill, and making your first Payment on Account.
- 31 July: Deadline for your second Payment on Account.
HMRC Penalty Structure
If you fail to file your online return by midnight on 31 January, HMRC issues an automatic £100 fixed penalty, even if you owe no tax. Returns filed more than 3 months late face daily penalties of £10 per day (up to £900), with further 5% penalties at 6 and 12 months.