As we approach the end of the calendar year and prepare for the start of the 2025/26 tax year, it’s essential to stay ahead of key dates and deadlines. Whether you’re in St Albans, Hemel Hempstead or beyond, being proactive with your accountant, getting important dates into your diary, and preparing for tax obligations, can help ensure a smoother financial year.

Staying organised is particularly important for tasks such as self-assessment submissions and the transition to Making Tax Digital (MTD). Early preparation not only helps you meet deadlines efficiently but also reduces the risk of penalties.

Here’s an updated list of the key dates for the 2025/26 tax year, with updates on MTD and other important deadlines for your accounting diary.

January 2025

• 31 January - Final online filing deadline for self-assessment income tax returns. Get ready to file your self-assessment or prepare all necessary documents for your accountant to ensure timely submission.
• 31 January - Deadline for settling balance of personal tax liabilities for 2023/24 tax year
• 31 January - Deadline for settling first payment-on-account for personal tax liabilities for 2024/25 tax year

April 2025

• 5 April - End of the 2024/25 tax year. Last day to make ISA contributions for 2024/25 or fill unused carry-forward pension annual allowance for 2021/22 tax year.
• 6 April - Start of the 2025/26 tax year. The new tax year begins, bringing changes to tax rates and allowances. It's essential to check for any updates in tax rules that could impact your filings.

Speaking to your local accountant in St Albans can help you understand how these changes might affect your income, investments, or business. They can provide tailored advice to ensure you stay compliant, optimise tax savings, and plan effectively for the year ahead.

Some key changes include:

• National Insurance contributions (NICs) will increase by 1.2 percentage points to 15%, and the annual threshold for employers to start paying NICs will reduce to £5,000
• The National Minimum Wage for 18-20 year olds rises to £10 an hour and the living wage for people aged 21 and older will rise to £12.21
• Both types of state pension rise by 4.1%
• The existing non-dom tax regime will be abolished
• 6 April - Marks a year to MTD for ITSA for those earning £50,000. With the transition to MTD for ITSA scheduled for April 2026, it’s wise to start transitioning to compatible software well ahead of time
• 19 April - Deadline for employers to submit a Full Payment Summary (FPS) and Employer Payment Summary (EPS) for the previous tax year
• 30 April - Self-assessment penalties take effect

May 2025

• 31 May - Deadline for P60s for employees who were on your payroll on the 5th of April 2024.

July 2025

• 5 July - Deadline for providing P60s and P11Ds to employees. All employers must ensure that they’ve shared P60s and P11Ds with employees by this date
• 6 July - Deadline for employers to report the total Class 1A National Insurance they owe
• 22 July - Employers must pay Class 1A National Insurance contributions by this date (by 19 July if paying by cheque)
• 31 July - The second payment on account for self-assessment is due on 31 July. Make sure, if you are self-employed or have additional sources of income, to settle any outstanding tax

Please note: If your P11D(b) is submitted late, you’ll get a penalty of £100 per 50 employees for each month. You’ll also be charged penalties and interest if you’re late paying HMRC.

As a small business, your accountant should be managing this for you, ensuring that your accounts department is prepared and ready to make payments. 

October 2025

• 5 October - Deadline to notify HMRC if you're required to file a self-assessment tax return (worth reminding newly self-employed or those who need to file a self-assessment return for the first time)
• 22 October - Pay tax and Class 1B National Insurance if you have a PAYE settlement agreement (by 19 October if paying by cheque)
• 31 October - Deadline to file your 2024-25 self-assessment tax year return if filing a paper return

January 2026

• 31 January - Self-assessment tax return deadline. One of the most critical dates of the year!
• 31 January - Along with the self-assessment return, the first payment on account for the 2025/26 tax year is also due

If you’re concerned about the amount of tax you may need to pay in 2026, now is the perfect time to consult your accountant. Early planning allows them to implement effective tax mitigation strategies, giving you more opportunities to reduce your liabilities. When it comes to managing taxes, it’s never too early to start preparing.

April 2026

• 6 April - Start of the 2026/27 tax year, bringing updated tax rates and possible reforms

Additional key accounting dates:

• Corporation Tax filing deadlines: Companies need to file their corporation tax returns within 12 months of the end of the accounting period
• VAT Returns: Businesses that file quarterly VAT returns should ensure timely submission to avoid penalties. The dates for VAT returns in the 2025/26 tax year depend on the quarter end but typically fall on:
  • 7 May
  • 7 August
  • 7 October
  • 7 February respectively

Accountant James Murray in St Albans said:

“As the 2025/26 tax year approaches, it's crucial for us accountants to keep track of these key deadlines to help our local clients, in and around St Albans, meet their obligations. The shift to MTD for Income Tax Self-Assessment will be a major change, so early preparation is important. Here at Visionary Accountants we are organised and proactive, so we can help our clients navigate the tax year with confidence, avoiding penalties and making sure everything is filed on time.”

At Visionary Accountants, we’re here to keep you in the know about the latest legislative changes that might affect you. If you want to stay up to date, we suggest signing up for our newsletter (using either of the forms below) or content with us on social media.