The UK tax year runs from 6 April to 5 April — an oddly specific date that trips people up, especially anyone used to a calendar-year system elsewhere.
Where the date actually comes from
It traces back to the old Julian calendar and the switch to the Gregorian calendar in 1752, when 11 days were skipped to align the calendars. The tax year originally ended on 25 March (Lady Day, a traditional quarter day), and shifted by 11 days to preserve a full year’s worth of tax collection — landing on 5 April, where it’s stuck ever since.
Why it still matters today
All the figures you see quoted as “2026/27” — Personal Allowance, tax bands, ISA limits — apply specifically to income and activity between 6 April 2026 and 5 April 2027. Getting your dates wrong when working out which year’s rules apply to you is a genuinely common, easily avoided mistake.
Use the Payslp Finance Hub for the current year’s rates and allowances.
Why some other countries use the calendar year instead
Many countries, including the US, simply use the calendar year (1 January to 31 December) for tax purposes — the UK’s 6 April start date is a genuine historical quirk rather than a deliberate modern design choice, which is exactly why it surprises people used to other systems.
Frequently asked questions
Does the tax year date ever change?
There’s occasional discussion about aligning it with the calendar year, but no confirmed change has been made — 6 April to 5 April remains the current UK tax year.
What’s the difference between a “tax year” and a “financial year”?
The personal tax year (6 April–5 April) is different from the government’s financial year (1 April–31 March) used for Budget and public spending purposes — easy to conflate, but genuinely separate concepts.