TL;DR: The UK personal tax year ends on 5 April each year. The next tax year starts on 6 April. The 5 April date is a long-standing historical artefact dating back to the change from the Julian to the Gregorian calendar in 1752 and a subsequent adjustment in 1800. The end of the tax year is the deadline for many personal finance actions: using the annual ISA allowance (20,000 pounds for 2026-27), using the pension annual allowance (typically 60,000 pounds), using the Capital Gains Tax exemption (3,000 pounds), and using the Inheritance Tax annual gift allowance (3,000 pounds). The corporation tax year for businesses is different (the financial year used by HMRC runs to 31 March), and accounting periods are set by each company.
Last reviewed May 2026
The UK tax year for personal income tax, capital gains tax, inheritance tax and several allowances runs from 6 April to 5 April. The 5 April end-of-year date drives the deadlines and use-it-or-lose-it timings for many personal finance actions. Knowing exactly what counts as "the end of the tax year" and which deadlines apply to which actions is essential for personal financial planning.
This guide explains the tax year dates for each main UK tax, the historical origin of the 5 April date, the practical actions that depend on the year end, the deadlines for filing tax returns and paying tax, and the differences between the personal tax year and the corporation tax year for businesses.
The personal tax year: 6 April to 5 April
The personal tax year in the UK runs from 6 April in one calendar year to 5 April in the next calendar year. The 2026-27 tax year therefore runs from 6 April 2026 to 5 April 2027. The 2027-28 tax year starts on 6 April 2027 and ends on 5 April 2028. The tax year is sometimes referred to by the two calendar years it spans (2026-27) or by the year in which it ends (the year ending 5 April 2027).
The 5 April date dates back to the move from the Julian to the Gregorian calendar in 1752 and a subsequent adjustment in 1800. The original tax year ended on 25 March (Lady Day, one of the four quarter days). When the calendar was reformed and 11 days were dropped, the Treasury adjusted the tax year end to keep the same effective annual period in revenue terms. A further day was added in 1800 to keep the alignment with leap year rules, producing the current 5 April date.
The 5 April end applies to income tax, capital gains tax, and the personal allowances and reliefs administered under those taxes (the ISA allowance, the pension annual allowance, the CGT exemption, the dividend allowance, the personal savings allowance, and so on). The use-it-or-lose-it allowances reset on 6 April.
Key year-end deadlines
The ISA allowance for 2026-27 is 20,000 pounds across all adult ISA types combined. Any allowance not used by 5 April 2027 is lost; it does not carry forward. Subscriptions made on or before 5 April count for the 2026-27 year; subscriptions on 6 April or later count for 2027-28. Many providers have earlier internal cut-off times for ISA subscriptions made by cheque or bank transfer near the deadline.
The pension annual allowance for 2026-27 is normally 60,000 pounds (subject to taper for higher earners and the Money Purchase Annual Allowance for those who have flexibly accessed a defined contribution pension). Unused annual allowance can be carried forward for up to three years, so the deadline is less absolute than the ISA, but contributions to use unused allowance must be made before 5 April in the relevant year.
The Capital Gains Tax annual exemption for 2026-27 is 3,000 pounds (down from 12,300 pounds in 2022-23 after two reductions). Gains realised by 5 April 2027 fall within the 2026-27 tax year; gains realised on 6 April or later fall within 2027-28. Spread-disposal planning to use successive years' exemptions is constrained by the lower current exemption.
The Inheritance Tax annual gift allowance is 3,000 pounds per donor per tax year, with any unused allowance from the previous year carrying forward once (so a maximum of 6,000 pounds in a year where the prior year was unused). The allowance refreshes on 6 April.
Self-assessment tax return deadlines
Self-assessment tax returns for the year ending 5 April are due online by the following 31 January. The 2026-27 tax return (covering the year ending 5 April 2027) is due online by 31 January 2028. The paper return deadline is 31 October 2027.
The tax payment for the year is also due by 31 January. For taxpayers with a tax bill above 1,000 pounds (and where less than 80 percent of the tax is collected at source), "payments on account" apply: half of the previous year's tax bill is due on 31 January (for the upcoming year) and another half on 31 July. The balancing payment (up or down) is due on the next 31 January.
Registration for self-assessment for a new source of income (such as starting self-employment) is due by 5 October following the end of the tax year in which the source started. So a new sole trader who starts in May 2026 must register for self-assessment by 5 October 2027.
The corporation tax year and accounting periods
UK companies are not on the personal tax year. Each company sets its own accounting period (typically 12 months), and corporation tax is calculated on the profits of the accounting period. The accounting period can end on any date the company chooses, although HMRC uses 31 March as the "financial year" reference for setting corporation tax rates.
Corporation tax for an accounting period is due nine months and one day after the period end for standard companies, or in quarterly instalments during and after the period for "large" companies (taxable profits over 1.5 million pounds, adjusted for associated companies).
The corporation tax return (form CT600) is due 12 months after the end of the accounting period. The return and the tax payment have different deadlines, which catches some businesses out: the tax is due before the return.
PAYE tax year and employer obligations
The PAYE tax year aligns with the personal tax year, running from 6 April to 5 April. Employers run payroll for the 2026-27 tax year from the first April 2026 payroll to the last March 2027 payroll, and the year-end procedures are due in April 2027.
The main employer year-end obligations are: the final FPS (full payment submission) marked as the final submission of the year, due on the last payroll date of the tax year; P60s to all employees still in employment on 5 April, due by 31 May following the year end; and P11D and P11D(b) returns for benefits in kind, due by 6 July following the year end.
The week 53 issue can arise where the last payroll period of the year falls on a date that produces a 53rd weekly pay period (or, less commonly, a 54th). HMRC's published guidance covers the week 53 treatment in the employer's payroll software.
VAT and Making Tax Digital periods
VAT periods do not align with the personal or corporation tax year. Each VAT-registered business has its own VAT quarter cycle, typically ending in either March/June/September/December, January/April/July/October, or February/May/August/November. The cycle is allocated by HMRC at registration and can be changed by request.
The VAT return is due one month and seven days after the end of the VAT quarter. Making Tax Digital for VAT requires digital records and submission through compatible software. The VAT payment is due at the same time as the return, unless the business is on direct debit (when payment is taken three working days after the due date).
Annual accounting for VAT is available for businesses with turnover below a specified threshold, with one annual VAT return and interim payments through the year. This is a separate scheme from Making Tax Digital.
Practical year-end planning
A practical pre-5 April checklist for personal finances normally includes: use the ISA allowance to the extent affordable, top up pension contributions to use the annual allowance (and any carried-forward allowance), realise any capital gains within the 3,000 pound exemption, use the annual IHT gift allowance, claim any unused marriage allowance, and check the position on personal savings allowance and dividend allowance.
Higher earners should consider: salary sacrifice into pension to reduce taxable income below the 100,000 pound taper threshold for the personal allowance (which tapers away by 1 pound for every 2 pounds of income above 100,000), gift aid donations to extend the basic rate band, and the use of EIS, SEIS, VCT or other tax-incentivised investments where the personal circumstances support them.
The year-end is also a useful trigger for reviewing the tax code, the personal tax account, and the cumulative position on State Pension contributions through National Insurance. The personal tax account on GOV.UK is the central hub for personal tax matters and the relevant information is consolidated there.
How we verified this
This article reflects current GOV.UK and HMRC guidance on personal tax, capital gains tax, ISA rules, pension annual allowance, inheritance tax annual gift allowance, self-assessment deadlines, corporation tax, PAYE and VAT. The historical origin of the 5 April date reflects the calendar reforms of 1752 and 1800, recorded in the Treasury's published historical guidance. The Finance Act 2024 and subsequent Finance Acts have made significant changes to several allowances; the latest figures should be checked on GOV.UK for the relevant tax year.
Disclaimer: This article is general information about UK tax year dates and deadlines. It is not personal tax or financial advice. Specific deadlines and allowance levels can change at each annual budget and the right action in an individual case depends on personal circumstances. Anyone planning year-end tax actions should check the current rates and rules on GOV.UK or take advice from an FCA-authorised adviser or chartered tax adviser.
Frequently asked questions
When does the UK tax year end?
The UK personal tax year ends on 5 April each year. The 2026-27 tax year ends on 5 April 2027, and the 2027-28 tax year starts on 6 April 2027. The 5 April date applies to income tax, capital gains tax, inheritance tax and the related personal allowances and reliefs. Corporation tax accounting periods are set separately by each company.
Why does the UK tax year end on 5 April?
The 5 April date dates back to the move from the Julian to the Gregorian calendar in 1752 and a subsequent adjustment in 1800. The original tax year ended on 25 March (Lady Day). When the calendar was reformed and 11 days were dropped, the Treasury adjusted the tax year end to keep the same effective annual period. A further day was added in 1800 to keep alignment with leap year rules.
What is the deadline for using the ISA allowance?
5 April each year, for the ISA allowance for that tax year. The 2026-27 ISA allowance of 20,000 pounds must be used by 5 April 2027 or it is lost; ISA allowances do not carry forward. Many providers have earlier internal cut-off times for subscriptions near the deadline, particularly for cheque or bank transfer subscriptions, so checking the provider's cut-off in advance is sensible.
When is my self-assessment tax return due?
The online self-assessment tax return for the year ending 5 April is due by the following 31 January. The 2026-27 return (covering 6 April 2026 to 5 April 2027) is due online by 31 January 2028. The paper return deadline is 31 October 2027. The tax payment for the year is also due by 31 January, with payments on account on 31 January and 31 July.
Is the company tax year the same as the personal tax year?
No. UK companies set their own accounting periods, typically 12 months ending on any date the company chooses. HMRC uses 31 March as the "financial year" reference for setting corporation tax rates. Corporation tax for an accounting period is due nine months and one day after the period end for standard companies. The CT600 return is due 12 months after the period end.
