Self Assessment 31 January deadline
The single most important date in the personal tax calendar, file and pay by 31 January.
RR AccountantsLast updated: 2025-01-153 min read
What's due by 31 January
- Online Self Assessment tax return for the previous tax year (6 April to 5 April)
- Balancing payment of any tax owed
- First payment on account for the new tax year (if applicable)
Other Self Assessment dates worth diary-ing
- 5 October: deadline to register for Self Assessment if you became liable in the previous tax year
- 31 October: paper return deadline (if you're filing on paper rather than online)
- 31 January: online filing + balancing payment + first payment on account
- 31 July: second payment on account (if applicable)
If you'll miss it
- File anyway, even with estimates — that prevents the £100 late filing penalty
- Pay what you can before the deadline to limit late payment surcharges
- Set up Time to Pay if you can't settle in full
- If you've already missed it, file and pay as fast as possible — penalties escalate
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