Key Dates and Deadlines for the 2025/26 Tax Year

The 2025/26 tax year is here, bringing with it a fresh set of deadlines and key dates that small business owners need to keep on their radar. Staying ahead of these important dates can help you avoid last-minute stress, late penalties, and unexpected tax bills.

From Self Assessment deadlines to VAT returns and payroll submissions, being organised is crucial for keeping your business finances in check.

In this blog, we’ll guide you through the key tax dates for the 2025/26 tax year to keep you confident and on track with your business finances.

If you're already a client of BCT Accountants, we’ll be on hand to guide you through the important dates relevant to your business, ensuring you stay compliant and prepared.

6 April 2025: Start of the 2025/26 Tax Year

The new tax year begins on 6 April 2025, marking the commencement of new tax rates, thresholds, and regulations. It's advisable to review any changes that may affect your business operations.

6 July 2025: P11D and P11D(b) Submission

If you provide expenses and benefits to employees, submit forms P11D and P11D(b) to HMRC by 6 July 2025 and provide employees with copies.

31 July 2025: Second Payment on Account Due

For those under Self Assessment, the second payment on account for the 2024/25 tax year is due by 31 July 2025. This advance payment contributes towards your tax liability for the year.​

5 October 2025: Deadline to Register for Self Assessment

If you're newly self-employed or have untaxed income, you must register for Self Assessment by 5 October 2025 to file a return for the 2024/25 tax year.

31 October 2025: Paper Tax Return Submission Deadline

For those opting to file a paper tax return for the 2024/25 tax year, ensure it's submitted by 31 October 2025. Late submissions may incur penalties.​

30 December 2025: Online Tax Return for PAYE Coding

To have any owed tax collected through your PAYE tax code, submit your online tax return by 30 December 2025. This option is available if you owe less than £3,000.

31 January 2026: Online Tax Return and Payment Deadline

The deadline for submitting your online Self Assessment tax return for the 2024/25 tax year and paying any tax owed is 31 January 2026. This date also marks the first payment on account for the 2025/26 tax year.

Monthly PAYE and NICs Deadlines

• 19th of Each Month: Deadline for postal payments of PAYE and National Insurance Contributions (NICs) to HMRC.

• 22nd of Each Month: Deadline for electronic payments of PAYE and NICs.

Corporation Tax Deadlines

Corporation Tax deadlines vary based on your company's accounting period:​

• 9 Months and 1 Day After Accounting Period Ends: Payment of Corporation Tax is due.​

• 12 Months After Accounting Period Ends: Filing deadline for Corporation Tax Return (CT600).

Need a helping hand with your business tax planning for 2025/2026? Get in touch today with Catherine on 01423 431 889 or email catherine@bctaccountants.co.uk for your FREE consultation call.

Please note: all stats are accurate for the 2025/26 tax year.