Financial year vs tax year: when does each start and end?
What is the difference between the UK Tax Year (6 April to 5 April), Financial Year (1 April to 31 March), and Company Accounting Period? Apportionment rules and deadlines.
In one sentence
There is no single UK financial year. In 2026/27 the personal tax year runs from 6 April 2026 to 5 April 2027, the Corporation Tax financial year runs from 1 April 2026 to 31 March 2027, and a limited company's own year ends on its accounting reference date.
Quick answer
- UK Tax Year: 6 April to 5 April (Self Assessment, PAYE, Personal Allowance)
- Financial Year: 1 April to 31 March (Corporation Tax rates and government budget settings)
- Company Accounting Period: Custom 12 months based on incorporation date
- Company profits straddling 31 March are daily-apportioned between financial years
Financial year vs tax year: What is the difference in the UK?
For UK business owners, sole traders, and company directors, understanding the difference between the Tax Year, the government Financial Year, and your company's Accounting Period is critical for tax compliance.
Mixing up these dates leads to missed HMRC filing deadlines, incorrect tax return calculations, and unexpected late payment penalties.
When does the financial year start and end in the UK?
There is no single UK financial year. The dates depend on whose year you mean:
- Personal tax year: 6 April to 5 April. The 2026/27 tax year runs from 6 April 2026 to 5 April 2027.
- Corporation Tax financial year: 1 April to 31 March. The financial year starting 1 April 2026 ends on 31 March 2027.
- Your company's financial year: it ends on your accounting reference date, which can fall in any month and is on your Companies House record.
- A sole trader's accounting year: it can end on any date, but profit is taxed for the 6 April to 5 April tax year.
People say fiscal year or end of financial year for any of these, so check which one a deadline refers to. The 2025/26 tax year ended on 5 April 2026. See GOV.UK Income Tax rates and Personal Allowances and our UK tax calendar.
Key differences at a glance
| Year type | Exact date range | Who does it apply to? | Main tax filings |
|---|---|---|---|
| UK Tax Year | 6 April to 5 April | Individuals, Sole Traders, Partners, Employees | Self Assessment (SA100), PAYE P60s, Class 2/4 NI |
| Financial Year (HMRC) | 1 April to 31 March | Government & Corporation Tax Rate setting | Corporation Tax rates (19% / 25%) & budget updates |
| Company Accounting Period | Custom 12 months (e.g. 1 Jan to 31 Dec) | UK Limited Companies & LLPs | Statutory Accounts (Companies House) & CT600 Return |
1. The UK Tax Year (6 April to 5 April)
The UK personal tax year runs strictly from 6 April to 5 April the following year. This calendar date dates back to the calendar reform of 1752 and applies to:
- Self Assessment Returns: Reporting untaxed income, dividends, capital gains, and rental income.
- PAYE & Payroll: Employer tax codes, P60 annual summaries, and P11D benefit reporting run on this cycle.
- Individual Allowances: Your £12,570 Personal Allowance, £500 Dividend Allowance, and Capital Gains Tax exemption reset every 6 April.
2. The Government Financial Year (1 April to 31 March)
The UK Government's financial year runs from 1 April to 31 March. HMRC and HM Treasury use this period to set corporate tax policy, budget changes, and statutory allowances.
When HMRC announces changes to Corporation Tax rates (such as the 19% Small Profits Rate or 25% Main Rate), the new rates take effect on 1 April at the start of the financial year.
3. Company Accounting Period (Company Financial Year)
When you incorporate a limited company at Companies House, your company is given an Accounting Reference Date (ARD), usually set to the last day of the month in which the company was formed.
Your company financial year runs for 12 months ending on your ARD (for example, 1 July to 30 June). Unlike individuals, a limited company can choose to change its financial year end by filing Form AA01 at Companies House.
What deadlines follow your company's year end?
For a new company, the first accounting reference date is the last day of the month in which the first anniversary of incorporation falls. A company incorporated on 6 April 2025 has a first accounting reference date of 30 April 2026, then 30 April each year. The Corporation Tax accounting period is the time covered by the Company Tax Return. It cannot be longer than 12 months and is normally the same as the company financial year, but it can differ in the first year.
Example: a company with a year end of 31 March 2026, whose Corporation Tax accounting period is the same 12 months.
| What | Deadline rule | Date in this example |
|---|---|---|
| File annual accounts with Companies House (private company) | 9 months after the financial year ends | 31 December 2026 |
| Pay Corporation Tax, or tell HMRC none is due | 9 months and 1 day after the accounting period ends | 1 January 2027 |
| File the Company Tax Return (CT600) | 12 months after the accounting period ends | 31 March 2027 |
A company's first accounts are due 21 months after the date it registered with Companies House. Source: GOV.UK accounts and tax returns for private limited companies. For the detail, read our Corporation Tax deadlines guide and CT600 guide. To change a year end, a company files form AA01 with Companies House (see GOV.UK form AA01).
What happens when a company year straddles 31 March?
If your limited company accounting period spans across 31 March when Corporation Tax rates change, HMRC requires you to apportion your company profits on a daily basis between the two financial years.
Example Apportionment Calculation:
A company with a financial year ending 31 December 2026 has 90 days in Financial Year 2025 (up to 31 March) and 275 days in Financial Year 2026 (from 1 April). Profits are split proportionally to apply the correct tax rates for each period.
Basis Period Reform for Sole Traders
Historically, sole traders could choose any accounting year-end date (e.g. 31 December) and pay tax under the "current year basis".
Under HMRC's Basis Period Reform, all sole traders and partnerships are now taxed on profits arising in the actual tax year (6 April to 5 April), regardless of their accounting year end. This aligns sole traders for Making Tax Digital (MTD) for Income Tax.
You can still prepare accounts to any date. If your accounting year ends between 31 March and 4 April, you can treat it as ending on 5 April. A 31 March or 5 April year end can make your return simpler because you do not need to split profit between two sets of accounts. See GOV.UK guidance on the tax year basis.
Read our guide on UK Tax Calendar dates & filing deadlines or see how our year-end accounts & Corporation Tax service keeps your company compliant.
Unsure about your accounting year end or tax deadlines?
Book a 30-minute call with an experienced UK accountant. We will review your accounting reference dates, Corporation Tax calculations, and filing schedule.
Book a call →Frequently asked questions
What is the difference between a tax year and a calendar year?
A calendar year runs from 1 January to 31 December. The UK personal tax year runs from 6 April to 5 April, so it starts in one calendar year and ends in the next. Income Tax, Self Assessment and PAYE use the tax year, not the calendar year.
What is a company's tax year?
A company does not have a tax year in the personal sense. It pays Corporation Tax for each accounting period, which is normally the 12 months covered by its accounts. HMRC applies Corporation Tax rates by financial year, 1 April to 31 March, and splits profit by days if an accounting period straddles 31 March.
When does the financial year end in the UK?
It depends which year you mean. The personal tax year ends on 5 April, so the 2026/27 tax year ends on 5 April 2027. The Corporation Tax financial year ends on 31 March, so the financial year starting 1 April 2026 ends on 31 March 2027. A limited company's own financial year ends on its accounting reference date, which can be any date in the year.
When does the financial year start?
The personal tax year starts on 6 April and the Corporation Tax financial year starts on 1 April. The 2026/27 tax year began on 6 April 2026. A limited company's own financial year starts the day after its previous year end.
When does my company's financial year end?
On its accounting reference date. For a new company, the first accounting reference date is the last day of the month in which the first anniversary of incorporation falls, and it then repeats every year. A company incorporated on 6 April 2025 has a first accounting reference date of 30 April 2026, then 30 April each year. You can check your date by searching for your company at Companies House.
Is the UK fiscal year the same as the tax year?
No. People often say fiscal year for any of these, but the dates differ. The tax year for individuals runs from 6 April to 5 April. The government and Corporation Tax financial year runs from 1 April to 31 March. A company's own year end can be any date.
Can a company change its financial year end?
Yes. A company files form AA01 with Companies House to change its accounting reference date. The form must be received within the period allowed for delivering the accounts for the current or the immediately previous accounting reference period. A change can alter the Corporation Tax accounting period, so tell HMRC if the dates for your Company Tax Return change.
Do sole traders have a financial year?
A sole trader can prepare accounts to any date, but profit is taxed for the tax year, 6 April to 5 April. If the accounting year ends between 31 March and 4 April, it can be treated as ending on 5 April, which avoids splitting profit between two sets of accounts.
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