UK Tax & Accounting Deadlines 2026: Your Complete Guide – JSB Accountants Can Help
Keeping track of accounting and tax deadlines can be tricky, but missing them can lead to fines, interest charges, and unnecessary stress. To make things easier, we’ve put together a comprehensive guide to the key deadlines for 2026, from Self Assessment and PAYE to Corporation Tax, VAT, and company accounts. With JSB Accountants on your side, you don’t have to worry about navigating these deadlines alone.
January 2026
31 January 2026 – Self Assessment & Payments
File online Self Assessment tax returns for the 2024/25 tax year. Filing late can result in penalties and interest.
Pay any tax owed under Self Assessment for 2024/25.
First Payment on Account for 2025/26. These are advance payments toward next year’s tax bill, based on your previous year’s liability.
Class 2 National Insurance payment for the 2024/25 tax year (if applicable).
⚠️ Tip: Even if you can’t pay the full amount, filing on time helps minimise penalties.
🟢 JSB Accountants can assist with preparing and submitting your returns, ensuring you meet all deadlines and avoid unnecessary fines.
February 2026
1 February 2026 – Penalties Start
Interest and late filing penalties begin if the Self Assessment deadline was missed.
📌 The sooner you file, the less penalty you pay. HMRC adds £100 immediately for late returns, plus daily penalties after 3 months.
🟢 Our team at JSB Accountants can help you get back on track quickly if you’ve missed a deadline.
March 2026
31 March 2026 – Accounting Year-End for Many Companies
Marks the end of the accounting year for companies that align with the tax year.
Companies should begin preparing Corporation Tax returns, ensuring all income, expenses, and allowances are properly recorded.
💡 Pro tip: Preparing accounts early allows time to spot errors, make year-end adjustments, and plan tax-saving strategies.
🟢 JSB Accountants can guide your company through year-end accounting, helping to optimise tax planning and stay compliant.
April 2026
5 April 2026 – Tax Year Ends
The 2025/26 tax year ends. Ensure all income, expenses, and reliefs are correctly recorded.
6 April 2026 – New Tax Year Begins
The 2026/27 tax year starts.
Making Tax Digital (MTD) for Income Tax begins for individuals earning over £50,000 annually.
19 April 2026 – PAYE & NICs
Deadline for PAYE and Class 1 National Insurance contributions for March 2026.
💡 Tip: Setting up automated payroll submissions makes this process smoother.
🟢 JSB Accountants can handle payroll submissions and MTD reporting so you stay fully compliant with minimal hassle.
May 2026
31 May 2026 – Employee Reporting & CIS
Issue P60s to employees for the 2025/26 tax year.
CIS monthly return deadline for April 2026 (if applicable).
⚠️ Remember: P60s are essential for employees to complete their own tax returns.
🟢 We can prepare and distribute all employee reporting forms accurately and on time.
July 2026
6 July 2026 – Expense Reporting & P11D
File P11D and P11D(b) forms for employees receiving benefits or expenses.
Provide employees with their P11D forms.
31 July 2026 – Self Assessment & PAYE
Second Payment on Account for Self Assessment (2025/26).
PAYE quarterly return for the period ending 5 July 2026.
💡 Tip: Keeping records updated throughout the year reduces end-of-year stress.
🟢 JSB Accountants can manage your P11D submissions and Self Assessment payments efficiently.
October 2026
5 October 2026 – New Self Assessment Registrations
Deadline to register for Self Assessment if you became self-employed in 2025/26.
31 October 2026 – Paper Tax Returns
Last day to submit paper Self Assessment tax returns for 2025/26 (if you’re not filing online).
⚠️ Online filing is usually faster, more accurate, and allows more time before the 31 January payment deadline.
🟢 If you’re new to Self Assessment, JSB Accountants can help you register and guide you through the process.
December 2026
30 December 2026 – Online Tax Returns via PAYE
Deadline to submit online Self Assessment tax returns if you want HMRC to collect unpaid tax through PAYE.
💡 Tip: Using online services makes it easier to manage payments and avoid penalties.
🟢 Our team can ensure your online submissions are correct and submitted on time.
Other Important Dates
Corporation Tax Payments: Due 9 months and 1 day after your accounting period ends (e.g., 31 March 2026 year-end → 1 January 2027).
VAT Returns: Typically quarterly, due 1 month + 7 days after the period ends.
Annual Accounts Filing: File accounts with Companies House within 9 months of your company’s accounting year-end.
Payroll Submissions (RTI): Ensure monthly or quarterly reporting for PAYE and NICs is submitted on time.
🟢 JSB Accountants can provide a full-service solution for Corporation Tax, VAT, and payroll, making compliance simple and stress-free.
✅ Tips for Staying on Track
Mark your calendar with key dates — digital reminders help prevent missed deadlines.
Keep accurate records throughout the year.
Use digital tools: Accounting software and Making Tax Digital simplify submissions.
Get expert help: JSB Accountants can advise on tax planning, reporting, and compliance to save time and reduce errors.
With proactive planning and expert support from JSB Accountants, you can avoid penalties, reduce stress, and make the most of available tax allowances.
As a family-run company, we pride ourselves on providing a bespoke service tailored to your particular needs.
Above all, our objective is to save you time, money and effort in managing your accounts, leaving you free to focus on building your business.
Remember, you’re not alone, we’re always here to help if you have an accounts problem or query
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