When does the UK tax year start? Key dates explained

The UK tax year runs from 6 April to 5 April the following year. 

For example: 

• The 2025–2026 tax year runs from 6 April 2025 to 5 April 2026 
• The 2026–2027 tax year runs from 6 April 2026 to 5 April 2027 

These dates apply to most personal taxes in the UK, including Income Tax, PAYE and Self Assessment. 

If you earn money, claim tax relief or submit tax returns, these dates determine which tax year your income and expenses fall into. 

Why does the UK tax year start on 6 April? 

The timing goes back centuries, and it’s actually pretty interesting! 

Originally, the tax year began on 25th March, known as Lady Day, which was one of the traditional quarter days used for rents and taxes. 

When Britain adopted the Gregorian calendar in 1752, 11 days were removed from the calendar to correct the difference from the old Julian system. To avoid losing tax revenue, the government shifted the start of the tax year forward by the same amount. 

That’s why the tax year now begins on 6th April instead of 25th March. 

It might seem strange today, but the dates have stuck ever since, a little like daylight savings!  

Key UK tax year dates: 

There are a few important dates linked to the tax year that are worth remembering. Whether you’re self-employed, PAYE or working in payroll, this matters and effects everyone earning in the UK, so it’s important to understand what it means for you, your employer, and your employees. 

End of the current tax year: 5th April 

The tax year closes. After this date: 

• HMRC finalises PAYE calculations
• Self Assessment figures can be confirmed
• Tax refunds for the previous year may be calculated 

Start of the tax year: 6th April 

A new tax year begins. This is when: 

• Personal allowances reset
• Tax bands refresh
• New tax rules often take effect
• You can claim your tax refund for the tax year just closed 

Self Assessment registration deadline: 5th  October 

If you need to file a Self Assessment tax return for the first time, you must register by this date. 

Online Self Assessment deadline: 31st January 

The deadline to submit an online Self Assessment tax return for the previous tax year. 

For example: 

• The 2025–26 tax year must be filed by 31 January 2027 

This is also when any tax owed must usually be paid. 

You can learn more in our guide to Self Assessment tax returns. 

Payment on account deadline: 31st July 

If you make payments on account through Self Assessment, the second instalment is due on this date. 

Why does the tax year matter? 

The tax year affects more than just accountants and tax returns. It influences how your income, allowances and refunds are calculated. 

Here are a few additional reasons the dates matter: 

Your Personal Allowance resets 

Each tax year includes a Personal Allowance. This is the amount you can earn before paying Income Tax. 

For most people, the allowance is currently £12,570. This allowance applies per tax year, meaning it resets every 6th April. 

Tax refunds are calculated by tax year 

If you’ve paid too much tax, HMRC can review your position after the tax year ends. 

This might happen because: 

• Your tax code was incorrect
• You changed jobs mid-year
• You paid emergency tax
• You claimed work expenses 

We explain common scenarios in top reasons you might be owed a tax refund. 

 

What happens at the start of a new tax year? 

The start of the tax year is often when tax changes come into effect. 

These can include: 

• Changes to tax thresholds
• Updated National Insurance rates
• New allowances or reliefs
• Adjustments to pension rules 

It’s also when many people review their finances, check their tax code and look back at the previous year.

National Insurance Calculator

What happens after the tax year ends? 

Once the tax year closes on 5th April, HMRC begins reconciling the tax paid during the year. 

For PAYE employees, this may result in: 

• A P800 calculation showing you paid too much or too little tax 
• An adjustment to your tax code
• A tax refund 

Tax refunds don’t always happen automatically, so it’s worth checking your position. 

If you want to understand how long the process usually takes, see our guide to how long a HMRC tax refund takes. 

Can you still claim for previous tax years? 

Good news! Yes, in most cases you can claim tax relief or refunds going back four tax years. 

For example, during the 2026–2027 tax year, you can usually claim for: 

• 2025-2026
• 2024–2025
• 2023–2024
• 2022–2023 

After that, the claim window closes. 

Simple ways to stay on top of the tax year: 

Keeping track of the tax year does not have to be complicated, and a few simple habits can make things easier. 

1. Keep important tax dates noted 

Adding key deadlines to your calendar can help you avoid last-minute stress. 

Important ones include: 

• 5 October – Self Assessment registration
• 31 January – online filing deadline
• 31 July – payment on account

2. Keep records throughout the year 

If you’re self-employed or claim expenses, it helps to keep records organised. 

This includes: 

• receipts
• invoices
• mileage records
• bank statements 

Keeping everything together makes tax returns far simpler. 

3. Check your tax position each year 

Even if you pay tax through PAYE, it’s still worth checking whether everything is correct. 

Many people discover they’ve overpaid tax because of: 

• job changes
• emergency tax codes
• unclaimed expenses 

If you’re unsure, you can start with our tax rebate calculator to see if you might be owed money back. 

A quick recap 

The UK tax year runs from 6th April current year to 5th April the following year. 

These dates determine: 

• when your income is taxed
• when allowances apply
• when tax returns must be filed
• when refunds may be issued 

Understanding the tax year helps you stay organised, avoid penalties and make sure you are not paying more tax than you should. 

FAQs: 

Why does the UK tax year run from 6th April to 5th April? 

The UK tax year dates go back to 1752, when Britain switched from the Julian calendar to the Gregorian calendar. Eleven days were removed from the calendar to correct the difference between the two systems. To avoid losing tax revenue, the government shifted the start of the tax year from 25th March to 6th April. The dates have remained the same ever since. 

What tax year are we currently in? 

The current tax year runs from 6th April 2025 to 5th April 2026. 

When people refer to a tax year, they usually name it using both years. For example: 

• 2025–2026 tax year: 6 April 2025 to 5 April 2026 
• 2024–2025 tax year: 6 April 2024 to 5 April 2025 

Is the tax year the same as the financial year? 

Not exactly. 

The UK tax year runs from 6th April to 5th April and applies mainly to personal taxes such as Income Tax and Self Assessment. 

The financial year used by the UK government runs from 1st April to 31st March and is used for public spending and budgeting. 

Can you claim tax refunds from previous tax years? 

Yes. In most cases you can claim a tax refund going back four tax years. 

For example, during the 2025–2026 tax year, you can usually claim for: 

• 2024–2025
• 2023–2024
• 2022–2023
• 2021–2022