SELF-ASSESSMENT: KEY DEADLINES

ASESA Solutions Ltd - SELF-ASSESSMENT: KEY DEADLINES

Self-Assessment is HMRC’s system for collecting Income Tax from individuals and businesses whose income isn’t automatically taxed — for example, self-employed workers, partners in a business, or those with additional untaxed income. Most employees have tax deducted automatically through PAYE, but if your tax affairs are more complex, you’ll need to complete a Self-Assessment tax return each year.

HMRC requires that your Self-Assessment tax return and any tax due are received by the deadline — missing it may incur penalties.

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• Notify HMRC by 5 October

  If you need to file a Self-Assessment return for the previous tax year and haven’t done so before, you must register by 5 October.

  
  

  If you register later, HMRC will assign a return‐due date (usually 3 months from notification), but tax must still be paid by 31 January 2026 to avoid penalties.

  
  

• Paper returns — deadline 31 October 2025

  Paper returns for tax year 2024–25 must arrive at HMRC by 11:59 pm on 31 October 2025.

  
  

  You may complete them any time from 6 April 2025 onward, as long as they arrive by that date.

  
  

• Online returns — deadline 31 January 2026

  Online submission must be completed by 11:59 pm on 31 January 2026.

  
  

  If you wish to have your Self-Assessment bill collected via your tax code, you must submit by 30 December 2025.

  
  

• Payment of liabilities & payments on account

  Any tax owed must be paid by 31 January 2026.

  
  

  If you make “payments on account”, the second instalment is due 31 July.

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Hence, staying aware of your Self-Assessment deadlines ensures you avoid penalties and keep your tax affairs in order. Don’t wait until the last minute — gather your records early and file on time.