The key tax year and financial dates you need to know for 2026
Look ahead to the new year and get your financial calendar in shape
The dawn of a new calendar year, while not coinciding with the tax year, presents an opportune moment for individuals to scrutinise their finances and prepare for upcoming fiscal changes. The UK’s tax landscape has grown increasingly intricate in recent years, making it understandable why many find it a bewildering prospect.
Praveen Gupta, UK head of tax at Azets, notes that "the tax regime has become far more complex," a sentiment echoed by the continuous stream of legislative updates. "There’s been lots of changes, and even in the latest budget, there are changes which are going to take effect in 2026, 2027, and 2029," Gupta explains. Staying abreast of crucial deadlines, he adds, means "you’ve got a better chance of planning for when you might have to pay your tax liabilities."
This vigilance is particularly vital as one's tax position can shift unexpectedly. Fiscal drag, for instance, where frozen tax thresholds push salaries into higher bands, can lead to "a higher tax liability" without a corresponding real-terms pay rise. Another common pitfall highlighted by Gupta is the requirement to declare and pay tax on the sale of a residential property in the UK "within 60 days."
Ignoring these obligations carries significant financial repercussions. "From an HMRC point of view, if you make late payments, there’s more of an onerous penalty regime and interest," warns Gupta. Therefore, understanding and marking key financial dates is not merely good practice, but a crucial defence against avoidable fines and unexpected costs.
January 2026
January 1: The new energy price cap will kick in. Most households who pay for energy will see bills rise by 0.2%.
January 31: The online filing date for Self Assessment tax returns for the 2024/25 tax year is at midnight. As is the balancing payment. “The filing date is really important,” says Gupta. “There’s about 12 million individuals who have to file a tax return in the UK; each year, about two million file their tax returns late, so that gives them an automatic £100 fine.” You may also have to pay your first payment on account for the 2025/26 tax year – this goes towards your next bill.
April 2026
April 1: Good news for those on the National Living Wage and National Minimum Wage – new rates come in on April 1. “Those rates increase quite dramatically, and have been doing so for the last few years,” says Gupta.
The next new Ofgem energy price cap will also come into force – how it changes is set to be announced on February 25.
April 5: This date marks the end of the 2025/26 UK tax year and is the deadline for maxing out your ISA and pension allowances. “The ISA limit is £20,000, that runs from April 6-April 5 [the following year],” says Gupta. “There was a change announced this year around the ISA. From 2027 you can only put up to £12,000 into a cash ISA, but the individual limit for adults remains £20,000. But if you don’t use that within the year, you lose it.”
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April 6: Now we’re into a new tax year. With the start of the 2026/27 UK tax year comes the implementation of the new State Pension and new benefit rates. And crucially this year, Making Tax Digital (MTD) for Income Tax Self Assessment will begin for lots of sole traders and landlords. “That’s the biggest change in Self Assessment for the last 30 odd years,” says Gupta. “If you are a landlord or a sole trader with more than £50,000 of income, from next April, you’re going to have to make quarterly tax returns.”
He continues: “That’s quite a big burden, because not only will you have to do the tax return for the current year, which will need to be filed in January 2027, you’ve also got to do these quarterly returns.”
July 2026
July 31: For those who file a Self Assessment tax return, July 31 is when many people have to pay their second payment on account for the 2025/26 tax year.
August 2026
August 7: Time to submit a quarterly update, if involved in Making Tax Digital (MTD).
October 2026
October 5: Not registered for Self Assessment for the 2025/26 tax year yet? October 5 is the deadline.
October 31: “This is the date when you could file a paper return. It’s quite rare to file a paper return now, because most people would use a professional services advisor, or the HMRC system to file their returns,” says Gupta. But some people still love pen and paper.
November 2026
November 7: Time to submit another quarterly update, if involved in Making Tax Digital (MTD).
Gupta recommends setting up alerts for the dates that are relevant to your financial position, and if in doubt about dates or your tax status, seek advice either from a specialist financial firm or check out the HMRC website.