UK Tax Deadlines 2025–2026: The Exact Dates You Must Not Miss (Avoid Penalties)

Recent analysis reveals that HMRC collected £220 million in late filing penalties in 2023. It's the latest available figure for revenue from late tax penalties in the UK, as data for the following years hasn't been released yet. That's nearly a quarter of a billion pounds from ordinary business owners, many just like you.

Running a business is tough enough without accidentally handing over your profits to the taxman because of a missed deadline. Remember, HMRC doesn’t give you a personal heads-up when your deadline is approaching—they only send out generic reminders. Check here if you want to see what a tax return & payment notification from HMRC looks like in real life.

Whether you're a freelancer just starting, a seasoned limited company director, or managing a bustling construction firm, the UK tax calendar can feel like a minefield. One wrong step and you're hit with a fine. But what if you could make penalties a thing of the past?

In this guide, we'll give you the exact 2025-2026 tax dates you need to know. No jargon, no confusion—just a clear, simple calendar to keep you compliant, penalty-free, and focused on what you do best: running your business.

What tax year are we filing for in 2026?

The tax year you will be filing for in 2026 is the 2025-2026 tax year. This runs from April 6, 2025, to April 5, 2026. The tax return will be due by January 31, 2027.

What tax is due in January 2026?

The tax due in January 2026 includes your Self Assessment tax bill for the 2024-2025 tax year. This typically consists of any remaining balance owed for the 2024-2025 tax year and your first payment on account for the 2025-2026 tax year. Ensuring these payments are made by the January 31, 2026, deadline is crucial to avoid penalties and interest charges.

2025-26 Tax Year Dates Revealed – Don’t Miss Out

First things first, let’s get the basics right. The UK tax year doesn’t follow the calendar year.

• Starts: 6 April 2025
• Ends: 5 April 2026

Everything you earn between these dates falls into the "2025-26 Tax Year." That part is simple, but the deadlines for reporting and paying for this period are where things get tricky.

Self-Assessment Deadlines (Sole Traders & High Earners)

If you are

• Self-employed,
• Earn over £100k, or
• Have untaxed income (like crypto gains or dividends), Self-Assessment is your biggest annual event.

The panic usually sets in around Christmas, but if you mark these dates now, you can enjoy your festive break stress-free.

Key Self-Assessment Dates

What is "Payment on Account"?

This catches so many people out. If your tax bill is over £1,000, HMRC essentially asks you to pay next year's tax in advance, split into two chunks (January and July).

If you’re having a slower year than the last one, you can ask to reduce these payments—but be careful. If you reduce them too much and earn more than expected, you’ll be charged interest.

If you would like more information and to calculate payment on account, take a look at our blog here.

Limited Company Deadlines: Essential Dates for Directors & Owners

Are you running a limited company? Your tax deadlines aren’t the same as sole traders! Instead, they’re based on your company’s financial year-end. Don’t miss out—find out what you need to know today!

However, some fixed dates apply to payroll and reporting.

Corporation Tax: The "9 Months and 1 Day" Rule

This is the one that trips up most directors.

• Filing Deadline: You have 12 months after your accounting period ends to file your Company Tax Return (CT600).
• Payment Deadline: You only have 9 months and 1 day after your accounting period ends to actually pay the tax.

Example:
If your company year-end is 31 March 2026:

• Pay Corporation Tax by: 1 January 2027
• File Company Tax Return by: 31 March 2027

Pro Tip: Always aim to file and pay at the same time (the 9-month mark) so you don’t accidentally spend the tax money.

Companies House Requirements

Aside from tax, you must keep Companies House happy to avoid your company being struck off.

• Confirmation Statement: Due annually, usually within 14 days of your "review period" ending. This just confirms your office address, directors, and shareholders haven't changed.
• Annual Accounts: For private limited companies, you must file these 9 months after your financial year ends.

Employers: PAYE and Payroll Deadlines

If you hire staff (even if it's just yourself as a director), you are an employer in the eyes of HMRC. This means Real Time Information (RTI) submissions and monthly payments.

The Monthly Rhythm

• On or before payday: Send your Full Payment Submission (FPS) to HMRC.
• 19th of the following month: Deadline for paying PAYE/NIC if paying by post (avoid this if possible).
• 22nd of the following month: Deadline for paying PAYE/NIC electronically.

Key Annual Payroll Dates (2025-26)

VAT Deadlines: The Quarterly Cycle

If your turnover is over £90,000 (the current threshold), you likely submit VAT returns quarterly.

The golden rule for VAT is: 1 calendar month + 7 days.

If your VAT quarter ends on 31 March, your deadline to file AND pay is 7 May.

Note: If you use the Annual Accounting Scheme, your dates will differ. Check your VAT dashboard.

Construction Industry Scheme (CIS)

For our clients in construction, CIS is a monthly non-negotiable.

• Deadline: The 19th of every month.
• What to do: You must file your monthly return telling HMRC how much you’ve paid subcontractors. Check how to claim your CIS return here.
• The Risk: Even if you haven’t paid any subcontractors that month, you should file a "nil return" to avoid confusion and potential penalty notices. Missing a CIS deadline incurs an instant £100 fine which escalates quickly.

3 Essential Tips to Keep HMRC Happy (and Avoid Costly Penalties)

Worried you'll miss a tax deadline? Here's how the smartest business owners stay on top of their finances:

• Ditch the paper statements: HMRC is going digital, so waiting for a letter in the post is a thing of the past. Set digital reminders to stay ahead.
• Create a tax pot: The moment a client pays, transfer 20-30% of that invoice into a separate savings account. This way, your Payment on Account in January won't be a nasty surprise.
• Automate with software: Why stress when you can automate? Tools like Xero, QuickBooks, or FreeAgent send reminders and help you track everything, so you never miss a beat.

Key Takeaways

• Stay Organised: Utilise accounting tools like QuickBooks, Xero, or FreeAgent to track expenses, monitor revenues, and manage tax deadlines efficiently. These platforms send helpful reminders to ensure you never miss important dates.
• Meet Deadlines: Proactively preparing for HMRC deadlines can help avoid penalties and ensure smooth tax filing. Leverage reminders and alerts to stay on top of your obligations.
• Understand Tax Changes: Keep up-to-date with new tax regulations and policies, as they may impact your small business. Being informed allows you to adjust strategies and remain compliant.
• Maximise Deductions: Take advantage of tax deduction opportunities to reduce liabilities. Filing correctly and being aware of eligible deductions can result in significant savings.
• Rely on Resources: Use platforms or expert guidance tailored to small businesses for step-by-step assistance with tax filing. Simplified tools and clear instructions can reduce errors and streamline processes.

Never Miss a Deadline Again

Does looking at this list give you a headache? You aren't alone. Keeping track of P11Ds, POAs, and VAT quarters is a full-time job—and you already have one of those running your business.

At Debitam, we believe you shouldn’t have to become a tax expert just to run a company.

Our system is designed to take the mental load off your shoulders. We offer tailored reminder services and follow-up emails that ping you exactly when you need to take action—not too early that you forget, and definitely not too late.

If you want to ensure your 2025-2026 tax year is penalty-free, why not check out our services? Let us watch the calendar so you can watch your business grow.