While the end of the calendar year and the end of the tax year do not align, the start of a new 365-day cycle round the sun is still an excellent time to get your head around your finances – and prepare for what the new year will bring.
In recent years, “the tax regime has become far more complex,” says Praveen Gupta, UK head of tax at Azets, so it’s understandable that people can find things confusing. “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,” adds Gupta. Knowing key dates to keep track of means “you’ve got a better chance of planning for when you might have to pay your tax liabilities”.
This is especially the case when your tax position can change without you expecting it to, for instance, as a result of fiscal drag, tax thresholds being frozen and your salary falling into a higher tax band, “which then effectively means that you’ve got a higher tax liability”. Gupta says another thing which can catch people out is “if you sell a residential property in the UK, you need to make a return and pay the tax due on the residential sale of that property within 60 days”.
Being aware of key tax return dates means you’re less likely to incur fines too. “From an HMRC point of view, if you make late payments, there’s more of an onerous penalty regime and interest,” says Gupta. So, here are some key financial dates for your diary…
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.”