UK Tax Calendar
Key UK tax deadlines for 2025/26 and 2026/27 tax years. Stay ahead of your obligations.
January 2026
Self-Assessment Deadline (2024/25)
Online self-assessment tax return deadline for 2024/25 tax year. Balancing payment due. 1st payment on account for 2025/26.
April 2026
End of 2025/26 Tax Year
Last day of the 2025/26 tax year. Ensure all tax planning actions for the year are completed.
Start of 2026/27 Tax Year
First day of the new 2026/27 tax year. New rates and allowances take effect.
May 2026
P60 Deadline
Employers must issue P60 certificates to all employees who were employed on 5 April 2026.
July 2026
P11D Deadline
Employers must submit P11D forms to HMRC for benefits in kind and expenses provided to employees in 2025/26.
Class 1A NIC Payment Deadline
Employers must pay Class 1A National Insurance contributions on benefits in kind reported on P11D forms.
2nd Payment on Account (2025/26)
Second payment on account for the 2025/26 tax year is due.
October 2026
Notify HMRC of New Income Source
Deadline to notify HMRC of new self-employment or other taxable income source that started in 2025/26.
Paper Self-Assessment Deadline (2025/26)
Paper self-assessment tax return deadline for the 2025/26 tax year. File on paper by this date or file online by 31 January 2027.
December 2026
Online Filing for PAYE Coding (2025/26)
Deadline for online filing if you want your 2025/26 tax collected through your PAYE code.
CT600 - Year End 31 Dec 2025
Corporation Tax return (CT600) due 12 months after the end of accounting period (31 December 2025). Corporation Tax payment was due by 1 October 2026 (9 months after period end).
January 2027
Online Self-Assessment Deadline (2025/26)
Online self-assessment tax return deadline for 2025/26. Balancing payment due. 1st payment on account for 2026/27.
March 2027
CT600 - Year End 31 Mar 2026
Corporation Tax return (CT600) due 12 months after accounting period ending 31 March 2026. Corporation Tax payment due by 1 January 2027 (9 months after period end).
Corporation Tax Deadlines
CT600 returns are due 12 months after the end of the accounting period. Corporation Tax payments are due 9 months and 1 day after the period end. Large companies (profits over \u00A31.5m) must pay in quarterly instalments.