The 2025/26 tax year ended on 5 April 2026, and for most people the tax return for it is due online by 31 January 2027. Here are the dates to put in your diary, and what happens if you miss them.
The key dates
- 5 October 2026: register for Self Assessment if you need to file a return for 2025/26 and haven't done one before, for example because you started working for yourself
- 31 October 2026: deadline for paper tax returns
- 30 December 2026: file online by this date if you're employed or get a pension, owe less than £3,000, and would like the tax collected through your tax code instead of paying it in one go
- 31 January 2027: deadline for online tax returns, and for paying any tax you owe for 2025/26 plus your first payment on account for 2026/27
- 31 July 2027: second payment on account for 2026/27
What are payments on account?
If your last Self Assessment bill was £1,000 or more, HMRC will usually ask you to pay towards the next year's bill in advance, in two instalments due on 31 January and 31 July. Each is normally half of the previous year's bill. You don't have to make them if more than 80% of your tax was already collected at source, for example through PAYE.
Payments on account can come as a shock in your first year of self-employment, when you may have to pay a full year's tax plus half as much again in January. If your income is falling, you can ask HMRC to reduce them. We'll tell you what to expect.
Penalties for filing late
- an automatic £100 penalty as soon as the return is late, even if you owe no tax
- after three months, £10 a day for up to 90 days
- after six months, a further 5% of the tax due or £300, whichever is higher
- after twelve months, another 5% or £300, and more in some cases
Interest is also charged on tax that's paid late, and there are separate penalties for late payment.
If you're a Scottish taxpayer
If your main home is in Scotland, your earnings, pension and rental profits are taxed at Scottish rates. For 2025/26, the year this return covers, the bands were:
- Starter rate, 19%: £12,571 to £15,397
- Basic rate, 20%: £15,398 to £27,491
- Intermediate rate, 21%: £27,492 to £43,662
- Higher rate, 42%: £43,663 to £75,000
- Advanced rate, 45%: £75,001 to £125,140
- Top rate, 48%: over £125,140
These assume the standard £12,570 Personal Allowance. Savings and dividend income are taxed at UK rates. The rates for the current year are on our personal tax page.
Making Tax Digital for Income Tax
Since 6 April 2026, sole traders and landlords with qualifying income over £50,000 have had to keep digital records and send quarterly updates to HMRC. The threshold falls to £30,000 from April 2027 and £20,000 from April 2028. If that's you, now is a good time to move to cloud accounting software.
Let us take care of it
We complete and file Self Assessment tax returns for sole traders, landlords, directors and others across East Kilbride and South Lanarkshire, and tell you exactly what to pay and when. Book a free initial consultation or call 01355 708410.