If there’s one tax date we want you to remember, it’s 31 January 2026. By 11.59pm that night, HMRC needs two things from you: Your online Self Assessment tax return and payment of any tax you owe.

It’s one of those deadlines that sneaks up quickly, and missing it can mean penalties and interest, which no one needs. 

Even if you don’t yet know your exact profit for the year, you still need to submit a return. Waiting until everything feels “finished” is often what causes last-minute stress.

If you’re paying through payments on account, there’s also a second payment due on 31 July – but the big one most people need to focus on is still January. 

Top tip: you can estimate your tax bill before submitting your return, which makes budgeting much easier and helps avoid a nasty January surprise. 

In short – 31 January is the deadline that really matters, so getting things done early is always the least stressful option. 

Internet link: Self Assessment tax returns – Deadlines