Getting to grips with the UK tax year is an important step for any small business owner. While it may seem like there’s a lot to learn, you can start the new tax year off right with some proper planning.
To make sure you’re prepared, we’ve rounded up all you need to know. Learn more about:
What is the UK tax year?
The UK tax year runs from the 6 April to the 5 April the following year. Often referred to as the financial or fiscal year, it is the period on which all your business’s financial reporting is based.
But when does the tax year end? We’re currently in the 2024/25 tax year, which ends on 5 April 2025. We’ll then enter the 2025/26 tax year.
The UK is one of the only countries in the world whose tax year doesn’t match the calendar year. This is steeped in history and is due to the UK’s change from the Julian to the Gregorian calendar in 1752.
Because of this discrepancy, it’s important to know which tax year we’re in and the key dates within it. Understanding business tax can help you with budgeting and strategy – as well as avoiding potential fines from missed deadlines.
Key dates in the UK tax year
Keep reading for a rundown of the tax year dates you need to know. Whether you’re looking to avoid penalties or interest charges, or just want to make informed decisions about your finances, knowing these dates can help.
But it’s not just tax dates you need to be aware of. Make sure you know these other key dates for small businesses to plan for the upcoming year.
April 2025: beginning the new UK tax year
- 1 April: the national minimum wage increases 6.7 per cent to £12.21 an hour
- 5 April: the end of the 2024/25 tax year
- 6 April: the beginning of the 2025/26 tax year
- 6 April: National Insurance (NI) contributions raise from 1.2 per cent to 15 per cent, and the threshold for paying NI on an employee’s salary is reduced from £9,100 to £5,000
- 19 April: deadline for PAYE submissions from the previous tax year (2024/5)
- 19 April: deadline for the final payments made by post for 2024/25 PAYE tax and Class 1 NICs
- 22 April: deadline for the final payments made electronically for 2024/25 PAYE tax and Class 1 NICs
- 30 April: the date daily penalties start for those who haven’t filed their Self Assessment (due 31 January)
May 2025
- 31 May: deadline for issuing your employees with a P60 form – summarising their total pay and deductions for the previous tax year
July 2025
- 6 July: P11D forms are due on this day each year – you’ll need to submit this if you offer employee benefits like company cars or season ticket loans
- 31 July: your second Self Assessment payment on account for the 2024-25 tax year is due
September 2025
15 September: this day marks Pension Awareness Day, making it a perfect time to start thinking about setting up a self-employed pension
October 2025
- 5 October: potentially one of the most important tax year dates for the newly self-employed, this is the date to register for Self Assessment – following the end of the tax year you became self-employed
- 31 October: if you’re submitting your tax return by post, this is the deadline for submitting your Self Assessment for the previous tax year
- TBC: the Labour government’s next Autumn Budget will likely take place at the end of October or the start of November – and is a key date for small business owners to remember
January 2026
- 31 January: online Self Assessments are due by this date – but you can submit them earlier if you wish to. Make sure you keep accurate tax records throughout the year to help avoid a last-minute panic
- 31 January: your first payment on account for the 2025-26 tax year is due on this date
- 31 January: if you’ve sold or disposed of any business assets, then you’ll need to pay capital gains tax by this date
- 31 January: this is the deadline for paying your Self Assessment tax return – even if you’ve submitted it earlier in the tax year – so don’t forget
March 2026
- TBC: the government’s Spring Budget is set to take place in March, which could bring major changes which affect small businesses
How to make effective preparations for these dates
Now that you know the key tax year dates for the upcoming year, there are a few ways to help prepare. Firstly, add these dates to your calendar and even consider setting up reminders in advance to give yourself time to prepare.
Another way to prepare is by familiarising yourself with the HMRC app. Spend some time getting to know where everything is so there’s no holdups as tax deadlines approach.
Most importantly: don’t wait until the end of the tax year to scramble for receipts and invoices by keeping track of your income and expenses throughout the year. This process can be as simple as using a notebook or spreadsheet, or you could invest in a dedicated accounting app. Find what works best for you and stick with it.
Don’t forget to check which self-employed expenses are tax deductible when saving your receipts.
Final tips for preparing for the tax year
Whether you’re newly self-employed or a seasoned pro looking to streamline your tax year preparations, reviewing these important tax year dates is a good starting point:
- When does the tax year end? The current tax year ends on 5 April 2025.
- When does the new tax year start? The new tax year starts on 6 April 2025.
- When are taxes due? Your Self Assessment tax return needs to be paid by 31 January.
If you’re still unsure about paying taxes, or if your business’s taxes are more complicated, you can always consider hiring an accountant. Looking into how much an accountant costs can help you budget for this in the future.
FAQ: some common questions
Do the dates of the tax year ever change?
While the tax year begins on the 6 April each year and doesn’t change, specific dates within the tax year could change.
Make sure you stay informed about any updates to tax laws, regulations, and deadlines within the tax year. The Autumn and Spring budgets often reveal such changes. You can also follow our socials and sign up for our newsletter to stay in the loop.
What’s the difference between the tax and the financial year?
While the terms are often used interchangeably, there’s a slight difference between tax year and financial year. The dates of the tax year are set by the UK government, while a company’s financial year is chosen by the company.
Can I claim tax relief for expenses incurred outside of the tax year?
You can generally only claim tax relief for expenses within the current tax year. However, there are exceptions to this rule – such as if you use accrual accounting. Make sure to speak with an accountant if you’re unsure of the exceptions.
What is the 183 day rule in the UK?
The 183 day rule affects people who live outside of the UK but still visit it more than 183 days in a year. If you visit more than this, you’ll need to pay tax in the UK.
How much can I earn before I pay 40% tax in the UK?
You’ll be charged 40 per cent tax at the Higher Rate if you earn between £50,271 and £125,140. Additionally, you’ll pay 45 per cent tax at the Additional Rate if you earn over £125,140.
Did you know business insurance is tax deductible?
Business insurance (such as public liability insurance) is an allowable expense you can claim while filing your tax return – while also helping to protect your small business. Why not get a tailored quote for business insurance today and start the new tax year off right?