HMRC Tax Calendar 2025–26
Every HMRC deadline.
In one place.
Key Self Assessment, CGT, P11D, and payment on account dates for 2025 and 2026. Updated for the 2024/25 and 2025/26 tax years.
Upcoming deadlines
31 July 2026Critical deadline
Second payment on account (2025/26)
Second advance payment for the 2025/26 tax year, based on 50% of the 2024/25 liability. Interest applies from this date on unpaid amounts.
Applies to: Self-employed and others with payments on account
Self Assessment Tax Returns Past deadlines (2025)
31 January 2025Online Self Assessment filing & payment
5 April 2025End of 2024/25 tax year
6 April 2025Start of 2025/26 tax year
30 April 202560-day CGT report: property disposals
31 May 2025P60 from employer deadline
6 July 2025P11D expenses & benefits deadline
31 July 2025Second payment on account
5 October 2025Register for Self Assessment
31 October 2025Paper Self Assessment return deadline
30 December 2025Elect to pay tax through PAYE code
31 January 2026Online Self Assessment filing & payment (2024/25)
Missed a deadline?
File as quickly as possible — penalties compound daily after 3 months. A Harrow accountant can file your outstanding return immediately and, where grounds exist, submit a formal penalty appeal.
Calculate your penalty firstKey penalty rates
Day 1 late filing£100 automatic
3 months late+£10/day (max £900)
6 months late+5% of tax or £300
12 months late+further 5% or £300
Late payment (30 days)5% surcharge
Interest on unpaid tax~7.5% p.a.
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