The 2025/26 tax year ended on 5 April 2026. If you are self-employed, a landlord, a company director with untaxed income or a higher earner with other income, your return is due online by 31 January 2027. That date also brings a tax payment, so leaving it to the last week costs more than sleep.
The key dates
- 5 October 2026: tell HMRC if you need to file a return for the first time.
- 31 October 2026: deadline for paper returns.
- 31 January 2027: online return, balancing payment for 2025/26 and first payment on account for 2026/27.
- 31 July 2027: second payment on account for 2026/27.
What to gather now
- Your Unique Taxpayer Reference (UTR) and Government Gateway login.
- P60, P45 or P11D if you were employed or received benefits.
- Self-employed income and expenses, ideally from your bookkeeping software.
- Rental income and costs, including mortgage interest statements.
- Bank and building society interest, dividends and any gains from selling shares or property.
- Pension contributions and Gift Aid donations, which can reduce your bill.
Payments on account, explained
If your last bill was over £1,000 and less than 80% of your tax was collected at source, HMRC asks for two advance payments towards next year, each half of this year’s bill. The first year this happens can feel like paying 150% at once. If your income has dropped, you can ask to reduce them — but only if you are confident, because interest applies if you reduce too far.
What happens if you miss it
A late return means an immediate £100 penalty, even if no tax is owed. After three months, daily penalties of £10 start, and further penalties follow at six and twelve months. Late payment adds interest and its own penalties.
How we help
We prepare and check your return, explain the numbers before anything is filed and tell you exactly what to pay and when. File early and you will know your January bill in November, with time to plan for it.
This article is general guidance based on the rules for the 2026/27 tax year. It isn’t personal advice — talk to us before you act on it.
