Key tax deadlines

Knowing your key tax deadlines is one of the simplest ways to reduce stress and avoid unnecessary HMRC penalties. For most UK individuals within Self Assessment, there are a few dates that really matter.

The UK tax year runs from 6 April to 5 April. After the year ends, you have time to gather your information and submit your Self Assessment return. If you’re filing online, the deadline is usually 31 January following the end of the tax year. For example, for the tax year ending 5 April 2024, the online filing deadline is 31 January 2025.

Paper tax returns have an earlier deadline, typically 31 October following the end of the tax year. Most people now file online, but if you prefer paper you must be even more aware of the shortened timescale.

The 31 January date is important for another reason: it’s also the deadline for paying any balancing tax due for the prior tax year, and for making your first “payment on account” for the current year, if applicable. A second payment on account may then be due on 31 July.

Missing these deadlines can lead to automatic penalties, interest on late payments and, over time, increasing costs if things remain unresolved. HMRC’s penalty system is largely automated and doesn’t take account of context unless you actively engage with them or ask an adviser to help.

Our advice is simple:

• Keep basic records throughout the year.

• Don’t wait until January to think about your return.

• Aim to file well before the deadline so there’s time to plan for any tax due.

We help clients map out their timeline, prepare information gradually and file in good time. With a clear view of your key dates, you can avoid last‑minute panic and stay firmly on top of your tax obligations.