Fiscal year vs financial year vs tax year in the UK

In the UK the tax year, often called the fiscal year, runs from 6 April to 5 April and is used for Income Tax, National Insurance and Capital Gains Tax. The financial year runs from 1 April to 31 March and is used for government budgets and Corporation Tax rates. A business’s own financial year, or accounting year, can end on any date it chooses.

The three UK years at a glance

Each year has a different start date and a different job. The table sets them side by side.

People use “fiscal year” loosely for any of these. In UK tax, “fiscal year” usually means the personal tax year, while HMRC and legislation use “financial year” for the 1 April to 31 March period.

What is the UK tax year?

The UK tax year runs from 6 April one year to 5 April the next. The current tax year, 2026/27, started on 6 April 2026 and ends on 5 April 2027.

Personal allowances, tax bands and National Insurance thresholds are all set for a tax year. Self Assessment returns also cover a tax year. GOV.UK’s Self Assessment deadlines page confirms that the 2025/26 return, for the year ended 5 April 2026, is due online by 11:59pm on 31 January 2027, with any tax owed paid by the same date. See our Self Assessment deadlines guide for the full calendar.

What is the financial year?

The financial year runs from 1 April to 31 March. The Interpretation Act 1978 defines it, for central taxes and public finance, as “the twelve months ending with 31st March.”

Corporation Tax rates are set for each financial year, named after the calendar year in which it starts. So the financial year 2026 runs from 1 April 2026 to 31 March 2027. GOV.UK’s Corporation Tax rates page gives a main rate of 25% and a small profits rate of 19%. If a company’s accounting period straddles 1 April and the rates change, HMRC says to “work out how many days each rate applied, then work out the tax due for each.” Our Corporation Tax rates 2026/27 page covers marginal relief.

What is a company’s financial year?

A company’s financial year is the period its annual accounts cover, ending on its accounting reference date (ARD). Companies House’s Life of a company guidance says a new company’s first ARD is “the last day of the month in which the anniversary of their incorporation falls.”

Companies House gives this example: a company incorporated on 6 April 2025 has a first ARD of 30 April 2026. Its first accounts therefore cover just under 13 months.

Key deadlines for a private company:

• accounts to Companies House: 9 months after the ARD
• first accounts over 12 months: 21 months from incorporation, or 3 months from the ARD if later
• Corporation Tax payment: usually 9 months and 1 day after the accounting period ends
• Company Tax Return: 12 months after the accounting period ends

Our guide to company accounts filing deadlines has worked dates.

How does the Corporation Tax accounting period differ?

A Corporation Tax accounting period “cannot be longer than 12 months”, according to GOV.UK’s accounting period guidance. If a company’s accounts cover more than 12 months, such as a 13-month first period, it must file two Company Tax Returns: one for the first 12 months and one for the remainder.

Can a company change its financial year?

Yes. Companies House lets a company change its year end. You can shorten it as often as you like, and lengthen it to a maximum of 18 months, normally no more than once every 5 years.

Which year applies to sole traders?

Sole traders and partners are taxed on the tax year, whatever date their accounts end. HMRC’s guidance on basis period reform says that from 6 April 2024 you report profit for each tax year, after 2023/24 acted as a transition year.

• If your accounts end between 31 March and 5 April, HMRC treats them as matching the tax year. No adjustment is needed.
• If your accounts end on another date, such as 31 December, you split profits from two sets of accounts across the tax year. The default method is by number of days.
• If you had transition profit from 2023/24, it is spread over later years, up to 2027/28.

Many sole traders choose a 31 March or 5 April year end to keep things simple. Under Making Tax Digital for Income Tax, quarterly updates also follow the tax year.

Which applies to you?

1. Employee or pensioner: the tax year, 6 April to 5 April.
2. Sole trader, partner or landlord: the tax year for tax, with accounts ideally ending 31 March or 5 April.
3. Limited company: your own financial year for accounts and Corporation Tax returns, with rates set by the 1 April to 31 March financial year.
4. Company director: both. Your company follows its own year; your salary and dividends are taxed in the tax year you receive them.

Frequently asked questions

Is the fiscal year the same as the tax year in the UK?

Usually, yes. In everyday use “fiscal year” means the personal tax year, 6 April to 5 April, though some people use it for the 1 April to 31 March financial year.

When does the 2026/27 tax year end?

The 2026/27 tax year ends on 5 April 2027. The 2027/28 tax year starts on 6 April 2027.

Does my company’s year end have to be 31 March?

No. A company can have any year end. It is set automatically on incorporation and can be changed through Companies House.

What is financial year 2026 for Corporation Tax?

Financial year 2026 runs from 1 April 2026 to 31 March 2027. Corporation Tax rates are set by reference to this period.