Tax Deadlines Card 2025-26

Key Dates

Deadline	Date
Register as self-employed	By 5 October after end of tax year you started
Self Assessment — online filing	31 January
Self Assessment — paper filing	31 October
SA balancing payment due	31 January
SA payment on account 1	31 January
SA payment on account 2	31 July
P60 issued to employees	By 31 May
P11D filing (benefits in kind)	By 6 July
CIS monthly return	By 19th of each month
VAT returns	Every 3 months (quarterly)
Corporation tax payment	9 months after accounting period end
CT600 filing	12 months after accounting period end

1 day late (SA)	£100 automatic
3 months late	£10/day for up to 90 days (max £900)
6 months late	£300 or 5% of tax due (whichever is greater)
12 months late	Further £300 or 5% of tax due

Late filing = automatic penalties. Set calendar reminders. Late payment interest is charged from the due date — even if you have a payment plan.