Introduction
Paying taxes is an unavoidable part of running a business, whether you operate as a sole trader, landlord, investor, or employer. These taxes may include income tax, VAT, corporation tax, and other obligations. However, unexpected business expenses can sometimes make it challenging to pay taxes on time. Knowing exactly when your tax obligations are due can give you the confidence to manage cash flow, prioritise spending, and even apply for short-term finance if needed.
This is why understanding the tax year is so important. Knowing exactly when a tax year starts and ends allows business owners to plan ahead, manage cash flow more effectively, and avoid costly penalties. Many assume the tax year follows the normal calendar year, but in the UK, that is not the case.
In this guide, we explain how the tax year works, why it is different from the calendar year, the key deadlines you need to know, and how business finance solutions can help if you are under pressure to pay on time.
What Is the Tax Year?
The tax year is the 12-month period HMRC uses to calculate how much tax you owe. During this period, all taxable income is recorded, assessed, and reported. This includes earnings from employment, self-employment, property, investments, and business profits.
Unlike the calendar year, which runs from 1 January to 31 December, the tax year runs from 6 April to 5 April the following year. For example, the 2025/26 tax year begins on 6 April 2025 and ends on 5 April 2026.
The tax year applies to:
Individuals paying income tax or capital gains tax
Self-employed individuals calculating profits and expenses
Employers submitting PAYE information
Landlords and investors reporting rental or investment income
If you spend 183 days or more in the UK during a tax year, you are usually considered a UK tax resident. This applies even if part of your income comes from outside the UK.
Why the Tax Year Matters for Businesses
The UK tax year’s unusual dates have historical roots. Originally, the tax year began on 25 March, known as Lady Day, which was one of the traditional quarter days used for rent and accounting.
In 1752, Britain adopted the Gregorian calendar, which required skipping 11 days to align with the rest of Europe. Rather than shortening the tax year, the government moved the start date forward to 5 April. A later leap year adjustment added another day, setting the start date at 6 April, where it remains today.
While it may feel outdated, this system has remained unchanged for centuries and is unlikely to change in the future.
For business owners, the tax year is more than just a date range. It determines when profits are assessed, when returns must be submitted, and when payments are due. Missing a deadline can result in penalties, interest, and unnecessary stress.
Understanding the tax year also helps with financial planning. When you know deadlines in advance, you can prioritise expenses, manage working capital, and explore funding options if cash flow is tight. Many businesses use short-term funding to cover tax liabilities while keeping day-to-day operations running smoothly.
For example, businesses often use VAT Loans to spread VAT payments over manageable monthly instalments, or Corporation Tax Loans to avoid large one-off payments.
Why the UK Tax Year Differs from the Calendar Year
The UK tax year’s unusual dates have historical roots. Originally, the tax year began on 25 March, known as Lady Day, which was one of the traditional quarter days used for rent and accounting.
In 1752, Britain adopted the Gregorian calendar, which required skipping 11 days to align with the rest of Europe. Rather than shortening the tax year, the government moved the start date forward to 5 April. A later leap year adjustment added another day, setting the start date at 6 April, where it remains today.
While it may feel outdated, this system has remained unchanged for centuries and is unlikely to change in the future.
Key Tax Deadlines You Need to Know
Understanding the tax year is only half the picture. Knowing the key deadlines is what helps you stay compliant and avoid penalties.
Self-Assessment Deadlines
If you are self-employed, a landlord, or have untaxed income, you must submit a self-assessment tax return.
Paper tax return deadline: 31 October after the end of the tax year
Online tax return deadline: 31 January after the end of the tax year
For example, for the 2025/26 tax year ending on 5 April 2026:
Paper return deadline: 31 October 2026
Online return deadline: 31 January 2027
If you struggle to pay your bill in full, Self Assessment Tax Loans can help spread the cost while keeping you compliant.
Tax Payment Dates
31 January: Balance due for the previous tax year, plus the first payment on account if required
31 July: Second payment on account (if applicable)
Late payments can result in interest and penalties, even if your return was submitted on time.
PAYE Deadlines for Employers
If you employ staff, you must submit PAYE information regularly:
Full Payment Submission (FPS): On or before employees’ payday
Employer Payment Summary (EPS): If applicable, submitted monthly
Final FPS and EPS: Due by 19 April after the end of the tax year
Failing to meet PAYE obligations can quickly lead to fines, making accurate payroll processes essential.
How the Tax Year Affects Different Types of Taxpayers
Employees
Employees usually pay tax through PAYE, which deducts income tax and National Insurance before wages are paid. At the end of the tax year, you receive a P60 summarising your earnings and deductions.
Self-Employed Individuals
Self-employed individuals pay tax on their net profit. This is calculated by deducting allowable business expenses from total income. The resulting figure is used to calculate income tax and National Insurance contributions.
If cash flow is unpredictable, business owners often use flexible funding such as Business Loans to manage peaks and troughs while meeting tax commitments.
Landlords and Investors
Landlords pay tax on rental income above the £1,000 property allowance. Capital gains tax applies when selling a property or investments. Investors are subject to the same tax rules on gains from shares or other assets.
For detailed tips on tax planning, check our related blog post: Maximizing Tax Benefits of Asset Finance for UK Limited Companies.
Managing Tax Bills When Cash Flow Is Tight
Even profitable businesses can struggle to pay tax bills on time. Late customer payments, seasonal income, or large upfront costs can leave a temporary cash shortfall.
This is where structured finance solutions can help. Depending on your situation, you may consider:
Asset Finance to release cash tied up in equipment
Invoice Finance to unlock funds from unpaid invoices
Car Finance to avoid large upfront vehicle costs
Using the right funding solution can help you stay compliant without disrupting operations or growth plans.
Tips to Stay on Top of Your Tax Year
Here are practical ways to ensure you never miss a tax deadline:
Keep Accurate Records – Store receipts, invoices, and financial documents in folders or accounting software.
Use Digital Tools – Apps and software can track deadlines and automate reminders.
Mark Deadlines on Your Calendar – Set recurring alerts for key dates, like 31 January for self-assessment.
Plan for Tax Payments – Treat taxes as a monthly expense and set aside funds regularly.
Get Professional Advice – An accountant or tax adviser can help maximise allowances and avoid mistakes. Learn more in our blog: Essential Benefits of Working with FCA-Regulated Finance Brokers.
Use Finance Solutions When Needed – Loans like Corporation Tax Loans, VAT Loans, or Self Assessment Tax Loans provide fast funding to meet deadlines without penalties.
By integrating these steps into your business routine, tax management becomes less stressful, helping you focus on growth.
Final Thoughts
The tax year plays a central role in how and when you pay tax. Understanding its structure, deadlines, and impact allows you to plan ahead, avoid penalties, and make informed financial decisions.
With the right preparation and access to flexible finance solutions, meeting tax obligations does not have to disrupt your business. Instead, it becomes a manageable part of running a successful and compliant operation.
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