UK tax deadlines 2026/27

The tax year itself

Before any deadline makes sense, it helps to know what the tax year actually is. For individuals the United Kingdom tax year runs from 6 April to 5 April. So the 2026/27 tax year began on 6 April 2026 and ends on 5 April 2027. Every personal deadline hangs off that.

The reason for the odd dates is historical rather than logical. Britain used to start its year on 25 March, and when the calendar was reformed in 1752 eleven days were dropped, pushing the date to 5 April. A further adjustment in 1800 moved the start to 6 April, and it has stayed there ever since. It is inconvenient but it is not going to change.

Companies are different. A company has its own accounting period, usually 12 months ending on whatever date it chose when it was formed, commonly the anniversary of incorporation. So two companies can have completely different corporation tax deadlines while both being perfectly on time. If you run a limited company, your deadlines depend on your year end, not on 5 April.

Self Assessment: the 31 January deadline

This is the date almost everyone means when they talk about the tax deadline. Your online Self Assessment return for the 2025/26 tax year, which ended on 5 April 2026, must reach HMRC by midnight on 31 January 2027. The tax you owe for that year must be paid by the same date.

Take Sarah, a self employed graphic designer. Her 2025/26 tax year ran from 6 April 2025 to 5 April 2026. She has from 6 April 2026 all the way to 31 January 2027 to file, which is almost 10 months. Most people still leave it to the last fortnight, which is how simple errors and missed expenses happen.

There are two other Self Assessment dates worth knowing. If you have never filed before and you need to, you must tell HMRC by 5 October following the end of the tax year. So somebody who started self employment in June 2026 must register by 5 October 2027. If you want to file on paper rather than online, the deadline is 31 October rather than 31 January, three months earlier.

The 31 July payment nobody expects

The second Self Assessment date is 31 July, and it causes more distress than any other date in the calendar because people do not see it coming.

If your tax bill is more than £1,000 and less than 80% of your tax was collected at source, HMRC asks you to make payments on account towards next year. Each one is half of last year's bill. The first is due on 31 January alongside the balancing payment for the year just gone, and the second is due on 31 July.

Here is what that looks like in practice. Sarah owes £4,000 for 2025/26. On 31 January 2027 she pays that £4,000 plus a first payment on account of £2,000 towards 2026/27, so £6,000 leaves her account. Then on 31 July 2027 a further £2,000 is due. Her first year in the system costs her one and a half years of tax in six months. Nobody warns you about this, and it is the single most common reason a new business runs into a cash problem in its second year.

Corporation tax: 9 months and 1 day

Limited companies pay corporation tax 9 months and 1 day after the end of the accounting period, and file the company tax return 12 months after the end of the period. Note that the payment comes first and the return comes later, which is the opposite of Self Assessment and catches out plenty of new directors.

A company with a 31 March 2026 year end must pay its corporation tax by 1 January 2027 and file its CT600 return by 31 March 2027. In practice you cannot know what to pay without doing the accounts, so the real working deadline is the payment date, not the filing date.

Very large companies, generally those with profits above £1.5 million, pay in quarterly instalments instead, starting before the year has even finished. That threshold is divided between associated companies, so a group of several small companies can find itself in the instalment regime unexpectedly.

VAT: 1 month and 7 days

If you are VAT registered, the return and the payment are both due 1 month and 7 days after the end of each VAT period. For a quarter ending 31 March, the deadline is 7 May. For a quarter ending 30 June, it is 7 August.

Two things matter here. The first is that the money must have cleared into HMRC's account by the deadline, not merely been sent, so a bank transfer started on the day may be late. The second is that VAT now uses a points based penalty system rather than an immediate fine. Each late return earns a point, and a penalty of £200 arrives only once you hit the threshold, which is 4 points for quarterly filers. Points expire after a period of compliance, but late payment penalties are separate and start after 15 days.

Employer deadlines

If you run a payroll, the deadlines are monthly rather than annual. A Full Payment Submission must reach HMRC on or before the day you pay your staff, not afterwards. PAYE and National Insurance must reach HMRC by the 22nd of the following month if you pay electronically, or the 19th if you still pay by post. Employers whose average monthly liability is under £1,500 can pay quarterly instead, on the 22nd after each quarter ends.

Then there are the annual dates. P60s must be given to every employee still working for you at 5 April by 31 May. P11D and P11D(b) forms reporting benefits in kind are due by 6 July, and the Class 1A National Insurance on those benefits must be paid by 22 July. From April 2027 most benefits will have to be payrolled instead, which removes the P11D for those items but brings the reporting forward into every pay run.

CIS deadlines

Contractors in the Construction Industry Scheme file a monthly return by the 19th of each month, covering the tax month that ended on the 5th. So the return for the month running 6 June to 5 July is due by 19 July. Payment of the deductions follows the ordinary PAYE dates, the 22nd electronically.

The penalty for a late CIS return starts at £100 and escalates quickly, and it applies even where you made no payments in the month, in which case a nil return is still required. Subcontractors have no monthly obligation, but they do need to file Self Assessment to reclaim the tax that has been deducted, and that is where most of them are owed a refund.

Companies House deadlines

Companies House is a separate body from HMRC with its own deadlines, and confusing the two is a common and expensive mistake. Annual accounts must be filed within 9 months of the financial year end for a private company. A company's very first accounts get longer, 21 months from the date of incorporation.

The confirmation statement, which simply confirms your company details are correct, is due within 14 days of the end of the review period, normally the anniversary of incorporation. Late filing penalties for accounts start at £150 for up to a month late, then £375, £750 and £1,500, and they double if you are late two years running. Unlike HMRC penalties, these are almost never waived.

The 60 day capital gains deadline

If you sell a residential property in the United Kingdom and there is capital gains tax to pay, you must report it and pay within 60 days of completion. This is a standalone return, separate from Self Assessment, and it still has to be reported again on your tax return at the end of the year.

Sixty days is a very short window when you are also moving house, and a great many landlords miss it simply because nobody told them it existed. The penalties follow the usual pattern of £100 and upwards. This deadline only applies to residential property and only where tax is actually due, so a sale covered entirely by private residence relief does not need reporting.

Making Tax Digital quarterly updates

This is the newest and biggest change to the calendar. From 6 April 2026, sole traders and landlords with qualifying income over £50,000 in the 2024/25 tax year must keep digital records and send quarterly updates to HMRC. The threshold falls to £30,000 from April 2027 and to £20,000 from April 2028.

For anyone using the standard tax year periods, the quarterly deadlines are 7 August, 7 November, 7 February and 7 May. Those replace nothing, they are in addition to your usual return, so an affected sole trader now has five submissions a year instead of one. Getting the bookkeeping onto software before April rather than after it is the difference between this being a minor administrative change and a genuine headache.

What actually happens when you miss one

For Self Assessment, £100 lands the day after the deadline whether or not you owe any tax. After 3 months daily penalties of £10 start, running up to £900. At 6 months another 5% of the tax due or £300 is added, whichever is greater, and the same again at 12 months. Late payment carries separate penalties at 30 days, 6 months and 12 months, plus daily interest throughout.

The important point is that penalties for filing late and penalties for paying late are two different things. If you cannot pay, you should still file on time. Filing keeps the £100 away, and it lets you set up a Time to Pay arrangement, which usually stops further penalties even though interest continues. Doing nothing is always the most expensive option.

How to stop missing them

The pattern I see most often is not laziness, it is that the deadline arrives before the records are ready. The fix is to work backwards. If your return is due on 31 January, set your own deadline for having the records complete at the end of September. That leaves four months of slack for the missing bank statement, the invoice nobody can find, and the question that needs an answer.

Put every date that applies to you in a calendar with a reminder a month ahead, not a week ahead. Keep tax money in a separate account so the deadline is a paperwork exercise rather than a cash crisis. And where a deadline depends on someone else, such as an accountant or a bookkeeper, agree the internal date with them in writing rather than assuming.

Frequently asked questions