Guide section 01
Which tax year is this about?
The 2025–26 UK tax year ran from 6 April 2025 to 5 April 2026. A return for that period brings together relevant income, allowable expenses and other tax information. Your filing responsibility depends on your circumstances, and an HMRC notice to file should be treated seriously even if you believe no tax is due.
Guide section 02
What are the main filing dates?
For a standard 2025–26 return, GOV.UK lists 31 October 2026 as the paper return deadline and 31 January 2027 as the online filing and payment deadline. Some situations have different dates, including a notice to file issued later than usual. Check the deadline that applies to your own return rather than relying only on a general calendar.
Guide section 03
When must a new filer tell HMRC?
If you need to complete a return and have not filed before, HMRC generally expects you to notify them by 5 October after the tax year. Registration can take time, so leaving it until January may create an avoidable problem. Check GOV.UK guidance if your circumstances changed during the year or you received a notice from HMRC.
Guide section 04
Which records should you gather?
Start with employment documents where relevant, business or rental income, bank information, invoices, expense evidence and information about pensions, investments or other taxable receipts. A separate list of missing items helps you request documents early. Good records also make it easier to explain how a figure on the return was calculated.
Guide section 05
Why prepare before the deadline?
Filing earlier can reveal the amount payable sooner, giving more time to plan cash flow; it does not normally move the standard payment deadline forward. It also leaves room to question an unexpected figure, correct bookkeeping and seek advice on a complex item before the last week of January.
Guide section 06
What if you have missed a date?
Do not ignore a late return or unpaid tax. Check the current HMRC instructions on penalties, interest and how to submit or amend a return. The right response depends on what is outstanding and why. Bringing the records up to date is usually a better first step than making an unsupported estimate.