UK Tax Year Dates 2026/27: Start, End and Every Key Deadline

The 2026/27 UK tax year starts on Monday 6 April 2026 and ends on Monday 5 April 2027. Those dates are the same everywhere in the UK — Scotland, Wales and Northern Ireland all use the same fiscal year, even though some tax rates differ. Everything else about personal tax hangs off them: allowances reset on 6 April, payroll tax weeks count forward from 6 April, and Self Assessment deadlines count forward from 5 April.

• 2026/27 runs 6 April 2026 to 5 April 2027. The previous year, 2025/26, ended on 5 April 2026.
• The quirky date comes from the old Lady Day year start plus the 1752 calendar change and an extra day added in 1800.
• Payroll splits the year into 12 tax months and 52 or 53 tax weeks, with month 1 running 6 April to 5 May.
• The big Self Assessment dates inside 2026/27 are 5 October 2026, 31 October 2026, 31 January 2027 and 31 July 2027.
• Allowances that reset on 6 April 2026 include the £12,570 Personal Allowance, the £20,000 ISA allowance, the £3,000 Capital Gains Tax exemption and the £500 dividend allowance.

Start and end of the 2026/27 tax year

A UK tax year always begins on 6 April and ends on 5 April the following calendar year. So when people ask "when does the tax year end", the answer for the current year is 5 April 2027 — and income you receive on 5 April 2027 falls in 2026/27, while income received on 6 April 2027 falls in 2027/28.

Two other year-ends often get confused with this one. Companies have their own accounting periods and the Corporation Tax financial year runs from 1 April, not 6 April. And if you are self-employed, your accounting period is now aligned to the tax year for Self Assessment purposes, so profits are reported to 5 April (or 31 March, which HMRC treats as equivalent).

Why 5 April? The short history

Until the mid-18th century the English legal and fiscal year began on Lady Day, 25 March. When Britain switched from the Julian to the Gregorian calendar in 1752, eleven days were removed from September that year. To avoid shortening the tax year and collecting less revenue, the year-end was pushed back by eleven days, moving the start from 25 March to 5 April.

Then in 1800 the two calendars diverged again: the Julian calendar treated 1800 as a leap year and the Gregorian did not. The Treasury added one more day, shifting the start of the tax year to 6 April, where it has stayed ever since. It has survived every attempt at tidying up largely because moving it would mean one short or long transitional year for every taxpayer, employer and pension scheme in the country.

Tax weeks and tax months in 2026/27

PAYE payroll does not use calendar months. It uses tax months that run from the 6th of one month to the 5th of the next, numbered 1 to 12 from April. Your payslip and your P60 use these numbers, and HMRC's PAYE payment deadlines follow them too.

Tax weeks 2026 work the same way. Week 1 runs from 6 April to 12 April 2026, week 2 from 13 to 19 April, and so on through week 52, which ends on 4 April 2027. Because 6 April 2026 falls on a Monday, weekly-paid staff whose pay day is a Monday will hit a week 53 on 5 April 2027. Week 53 gives an extra week's worth of free pay and NI threshold, which is why a small underpayment of income tax sometimes shows up for weekly-paid employees in a week 53 year.

Key deadlines during the 2026/27 tax year

Most deadlines that land inside 2026/27 relate to the tax year that has just finished, 2025/26. That lag is the single most common source of confusion.

If you are inside Making Tax Digital for Income Tax — which starts on 6 April 2026 for sole traders and landlords with gross self-employment or property income over £50,000 — you also have quarterly updates to send during the year, with deadlines of 7 August 2026, 7 November 2026, 7 February 2027 and 7 May 2027.

Full detail on the filing dates, penalties and payments on account is in our guide to Self Assessment tax return deadlines, and you can see what is coming next in the tax deadline tracker.

Worked example: when 2026/27 tax is actually paid

Take a sole trader with profits of £45,000 earned between 6 April 2026 and 5 April 2027.

• Taxable income: £45,000 − £12,570 Personal Allowance = £32,430, all within the £37,700 basic-rate band.
• Income tax at 20%: £32,430 × 0.20 = £6,486.
• Class 4 National Insurance at 6% on profits between £12,570 and £50,270: £32,430 × 0.06 = £1,945.80.
• Total for the year: £8,431.80.

None of that is due during 2026/27 itself. The return is filed by 31 January 2028, when the £8,431.80 balancing payment falls due — plus a first payment on account for 2027/28 of half that figure, £4,215.90, with a second £4,215.90 on 31 July 2028. So the first bill for income earned in April 2026 arrives almost 22 months later. Budgeting from the start of the tax year is what stops that being a shock.

What resets on 6 April 2026

The switch to a new tax year wipes the slate on annual allowances. Anything unused on 5 April is generally lost.

• Personal Allowance: £12,570, tapered away above £100,000 of adjusted net income.
• ISA allowance: £20,000 across all ISAs. The cash ISA limit is set to fall to £12,000 for under-65s from April 2027, so the 2026/27 allowance matters more than usual.
• Capital Gains Tax annual exempt amount: £3,000, with rates of 18% and 24% above it.
• Dividend allowance: £500, then 10.75%, 35.75% or 39.35%.
• Personal Savings Allowance: £1,000 for basic-rate taxpayers, £500 for higher rate, nil for additional rate.
• Pension annual allowance: £60,000, with unused allowance from the previous three years potentially carried forward.
• Trading and property allowances: £1,000 each; Rent-a-Room relief £7,500.
• Tax codes: HMRC issues new PAYE codes for the year, and payroll returns to week 1 / month 1.

In Scotland the dates and allowances are identical, but Scottish rates apply to non-savings, non-dividend income: a starter rate of 19%, basic 20%, intermediate 21%, higher 42%, advanced 45% and top rate 48%. Savings interest and dividends are taxed at the UK-wide rates wherever you live.

The 4-year time limit also runs from 5 April. Overpaid tax for 2022/23 must be claimed by 5 April 2027, and a Marriage Allowance claim made in 2026/27 can be backdated four years, worth up to £1,260 in total.

What to do next

If you want to use the allowances before they reset, work through the tax year end planner to see which ones apply to you and what the deadline is for each. To keep on top of filing and payment dates as they come round, bookmark the tax deadline tracker. You can register for Self Assessment or check your filing dates on GOV.UK.