- The 2026/27 UK tax year runs from 6 April 2026 to 5 April 2027, separate from the calendar and government financial years.
- Self Assessment has three dates that matter most: register by 5 October, file online by 31 January, and pay on account on 31 January and 31 July.
- Making Tax Digital for Income Tax is now live for sole traders and landlords earning over £50,000, with the first quarterly update due 7 August 2026.
UK tax year dates for 2026/27 run from 6 April 2026 to 5 April 2027, and they set the clock for every filing and payment you owe HMRC.
Miss one and the penalties start fast, so a single clear calendar is worth bookmarking. Good accounting support keeps every date tracked for you, but the full list below covers Self Assessment, Corporation Tax, VAT and PAYE in one place.
One big change is already here. Making Tax Digital for Income Tax went live on 6 April 2026 for sole traders and landlords earning over £50,000, so digital record-keeping is now the law, not a plan for later.
When does the UK tax year start and end?
The UK tax year runs from 6 April to 5 April the following year, so the 2026/27 tax year starts on 6 April 2026 and ends on 5 April 2027.
That’s different from the calendar year and from the government’s own financial year, which runs 1 April to 31 March. Your personal tax, payroll and Self Assessment deadlines all track the 6 April to 5 April cycle, even when your company accounts use a different year end.
If you want a refresher on how the bands and rates sit inside that year, our guide to UK tax brackets is a good place to start.
Why the tax year starts on 6 April
The date is a leftover from a calendar change. Britain switched from the Julian to the Gregorian calendar in 1752 and lost 11 days in the process.
The tax year had run from 25 March, an old quarter day known as Lady Day. To avoid losing revenue, the Treasury shifted the start forward by 11 days to 5 April, then moved it again to 6 April around 1800 to account for a leap year difference. It’s stuck ever since.
Tax weeks and tax months explained
Tax weeks and tax months both start on 6 April, not on calendar dates. A tax week is a seven day block, and a tax month runs from the 6th of one month to the 5th of the next.
Employers use these to calculate National Insurance and run payroll correctly. Tax month 1, for example, runs 6 April to 5 May, and tax week 1 runs 6 April to 12 April.
What are the key Self Assessment deadlines for 2026/27?
The Self Assessment deadlines you’ll return to most are 5 October to register, 31 October for paper returns, and 31 January for online returns and payment. The table below covers the 2025/26 return, which is the one you file during the 2026/27 tax year.
Action | Deadline |
Register for Self Assessment (first time, for 2025/26) | 5 October 2026 |
Submit a paper tax return for 2025/26 | 31 October 2026 |
Submit an online tax return for 2025/26 | 31 January 2027 |
Pay your 2025/26 tax bill and first payment on account for 2026/27 | 31 January 2027 |
Second payment on account for 2026/27 | 31 July 2027 |
Payments on account catch a lot of people out. Each one is half of your previous year’s tax bill, paid in advance, with the first due alongside your main bill on 31 January and the second on 31 July.
New to the process and can’t find your reference? Our guide on how to find your UTR number walks you through it. When you’re ready to file, filing your Self Assessment covers the steps in full.
What are the Corporation Tax and accounts deadlines?
Corporation Tax deadlines don’t follow the 6 April tax year. They hang off your company’s own accounting period, so every company’s dates are slightly different.
The one that surprises directors is the order: you pay your Corporation Tax before you file the return that works it out.
Requirement | Deadline |
Pay Corporation Tax | 9 months and 1 day after your accounting period ends |
File your Company Tax Return (CT600) | 12 months after your accounting period ends |
File annual accounts with Companies House | 9 months after your accounting reference date |
File your confirmation statement | Within 14 days of your review period ending |
Set a reminder for the 9 months and 1 day payment date the moment your year end passes, because it lands three months before the return itself and it's the one people forget.
For the detail on getting the return right, see our guide to Corporation Tax filing. If your confirmation statement has slipped, overdue confirmation statement explains how to fix it.
What are the VAT and PAYE deadlines?
VAT and PAYE run on their own repeating cycles rather than a single annual date, so they’re easy to lose track of once the year gets busy.
VAT deadlines
Most VAT-registered businesses file quarterly. The deadline to submit your return and pay is one calendar month and seven days after the quarter ends.
For a quarter ending 31 March, that means 7 May. All VAT-registered businesses must now file through Making Tax Digital for VAT using compatible software such as Xero or QuickBooks.
PAYE and payroll deadlines
If you run payroll, these dates repeat every tax month.
Action | Deadline |
Send your FPS (Full Payment Submission) | On or before each payday |
Send your EPS (Employer Payment Summary), if needed | By the 19th of the next tax month |
Pay PAYE and National Insurance electronically | By the 22nd of the next tax month |
Give employees their P60 | By 31 May 2027 |
Report expenses and benefits (P11D) | By 6 July 2027 |
What’s changed under Making Tax Digital for Income Tax?
Making Tax Digital for Income Tax is now in effect. Since 6 April 2026, sole traders and landlords with qualifying income over £50,000 have had to keep digital records and send HMRC quarterly updates through compatible software.
This is the biggest shift to Self Assessment in years, so it’s worth knowing exactly where you stand.
Who’s in scope and when
Qualifying income means your gross self-employment and property income added together, before expenses. The threshold drops over the next two years.
Qualifying income | Start date |
Over £50,000 | 6 April 2026 (now live) |
Over £30,000 | 6 April 2027 |
Over £20,000 | 6 April 2028 |
Limited companies aren’t affected and continue with Corporation Tax as normal.
The deadlines you can’t miss
If you’re in scope now, your first quarterly update covers 6 April to 5 July 2026 and is due by 7 August 2026. Three more quarterly updates follow, then a final declaration by 31 January 2027 replaces your old Self Assessment return.
For a full breakdown of how the rules work in practice, see our guide to Making Tax Digital for Income Tax.
What happens if I miss a tax deadline?
Missing a Self Assessment deadline triggers an automatic £100 penalty the day after 31 January, even if you owe no tax at all. From there it climbs quickly.
The penalties stack in stages:
- After 3 months late: £10 a day, up to a maximum of £900
- After 6 months late: a further £300 or 5% of the tax owed, whichever is higher
- After 12 months late: another £300 or 5% of the tax owed, whichever is higher
That’s at least £1,600 in penalties on a return that’s a year late, and interest runs on any unpaid tax from 1 February on top. Corporation Tax, VAT and PAYE carry their own separate penalty regimes, which our guide to HMRC and Companies House fines sets out in full.
How Sleek helps with UK tax year dates
Knowing the dates is one thing. Keeping every Self Assessment, Corporation Tax, VAT and PAYE deadline tracked across a full year, without a single one slipping, is where most business owners lose sleep.
Sleek’s accountants handle your filings and flag every deadline before it’s due, so you’re never scrambling in late January or facing an avoidable fine.
Disclaimer: The preceding information is not legal advice. This content is aimed to provide general guidance. For more formal or legal advice, contact Sleek directly.
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FAQs on UK tax year dates
Can I file my Self Assessment return as soon as the tax year ends?
Yes. The online service opens on 6 April, so you can file your 2025/26 return any time from 6 April 2026 onward. You don’t have to wait until January. Filing early tells you your exact bill months ahead, gives you longer to budget for it, and gets any refund back sooner. You can check the current deadlines on the official GOV.UK Self Assessment guidance.
Do the tax year dates ever change if 5 April falls on a weekend?
No. The tax year always ends on 5 April and starts on 6 April, regardless of which day of the week those dates land on. The dates themselves are fixed. What can shift is a filing or payment deadline: if a due date falls on a weekend or bank holiday, HMRC usually treats payment as on time if it clears the next working day.
Is the government financial year the same as the tax year?
No. The personal tax year runs 6 April to 5 April, while the government’s financial year runs 1 April to 31 March. They’re only days apart, which is why they get mixed up. Corporation Tax rates are set by the financial year, so a company with a year straddling 31 March can have two different rates apply across one accounting period.
When can I start paying into a new year’s ISA or pension allowance?
Your annual allowances reset on 6 April, the first day of the new tax year. From that date you get a fresh ISA allowance and a renewed pension annual allowance for 2026/27. Allowances don’t roll over if unused, apart from limited pension carry-forward rules, so the 5 April cut-off each year is effectively a use-it-or-lose-it deadline for that year’s ISA.
Does my company’s accounting period have to match the tax year?
No. You choose your company’s accounting reference date when you incorporate, and Companies House sets your first year end to the last day of the month you registered. Many directors align it with 31 March or 31 December for simplicity, but you’re free to pick another date. Your personal tax still follows 6 April to 5 April even when your company runs a different year.
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What’s the first VAT quarter deadline in the 2026/27 tax year?
It depends on your VAT stagger, since not everyone files for the same quarters. For a business whose quarter ends 30 June 2026, the return and payment are due by 7 August 2026, one calendar month and seven days after quarter end. Your VAT online account shows your exact periods, and all returns must go through Making Tax Digital compatible software.
If I register for Self Assessment late, do I still get the usual deadlines?
Not exactly. If you register after 5 October, HMRC writes to you with a filing deadline three months from the date of that letter, rather than the standard 31 October or 31 January. The catch is that your payment deadline doesn’t move. You still owe any tax by 31 January, and interest runs from 1 February if you pay late, even when your filing date has been extended.
