UK tax year dates

The UK tax year runs from 6 April to 5 April the following year. 2026/27 started on 6 April 2026 and ends on 5 April 2027. New Income Tax bands, National Insurance thresholds and student loan thresholds normally take effect on 6 April, and the tax return for a year is due online by 31 January after it ends.

The 2026/27 tax year at a glance

Date	What happens
6 April 2026	2026/27 tax year starts; new rates and thresholds apply to pay from this date
5 October 2026	Deadline to register for Self Assessment if you need to file for 2025/26 for the first time
31 January 2027	Online Self Assessment return for 2025/26 due, and any tax owed paid
5 April 2027	2026/27 tax year ends
6 April 2027	2027/28 tax year starts; savings Income Tax rates are due to rise from this date
31 January 2028	Online Self Assessment return for 2026/27 due

You will see the tax year written as 2026/27, 2026 to 2027 or 2026-27, all meaning the same twelve months.

What the tax year means for your pay

Income Tax through PAYE is cumulative across the tax year. Each payday, payroll looks at your total pay since 6 April and the tax-free allowance built up by that point, and works out the tax due so far. An underpayment in one month therefore usually corrects itself the next. Someone who starts a job partway through the year, having earned nothing earlier, can pay little or no tax for a while.

National Insurance is calculated on each pay period on its own, so there is no catching up across the year.

Your allowance resets on 6 April. A tax code adjusted during 2025/26 to collect something will normally be replaced by a new HMRC code for 2026/27, which your employer applies from the first payday after 6 April. Tax codes explained covers what the numbers and letters mean.

Which tax year a payment falls into

For employees the tax year follows the date you are paid, whatever date you did the work. Overtime worked in March but paid in April’s salary is taxed in the new year. Back pay works the same way: a pay award agreed in the autumn and backdated to April is taxed in the year it lands in your bank account.

Thresholds are where this matters. A large arrears payment can push your income for that year over £50,270, where 40 per cent tax starts in England, Wales and Northern Ireland, or over £60,000, where the High Income Child Benefit Charge begins.

April changes for public sector staff

Several public sector changes cluster in April.

• new Income Tax and National Insurance thresholds (for 2026/27 the main ones were frozen)
• new pension contribution bands in the NHS Pension Scheme, Teachers’ Pension Scheme, LGPS and Civil Service schemes, applied to your pay from 1 April or the first April payday
• NHS Agenda for Change and NJC pay awards, which run from 1 April each year
• the new National Living Wage, which rose to £12.71 an hour from 1 April 2026

Teachers in England follow a pay year that runs from 1 September, so the 2026 pay award applies from 1 September 2026 even though the tax year started in April.

End-of-year paperwork

After 5 April your employer gives you a P60 showing your pay and tax for the year. Keep it for checking your tax, claiming a refund, applying for some loans or filling in a tax return. If you left a job during the year, your P45 does the same for that employment. P45, P60 and P11D explained lists what each form shows and when to expect it.

Deadlines that look back over several years

Some claims can be backdated. Tax relief for uniform and work clothing goes back up to four previous tax years, so a claim made in 2026/27 can reach 2022/23. Each relief has its own rule, so check the one you need.

If you think you need to file a tax return, register by 5 October after the end of the tax year concerned. Do employees need to do Self Assessment? covers who has to.