Register for Self Assessment by 5 October: side income over £1,000, rent, selling on Vinted and eBay
Monday 5 October is the deadline to register for Self Assessment for anyone who received untaxed income for the first time in the tax year from 6 April 2025 to 5 April 2026: a side hustle over £1,000, letting out property, dividends, crypto gains. Online platforms — eBay, Vinted, Airbnb, Uber — already report their sellers' data to HMRC. Registration is free and takes minutes, while a late tax return starts with a £100 penalty.
HMRC is signing up sole traders and landlords to Making Tax Digital automatically — next deadline 7 November
Since 6 April 2026, anyone with more than £50,000 of income from self-employment and property must report four times a year. Those who did not sign up are now being enrolled by HMRC itself: letters started going out in September, after the event. 436,000 people have filed a first update; the next deadline is 7 November 2026.
HMRC to issue tax calculations on bank interest from late September: what to check in P800 and PA302
HMRC says it will start issuing P800 calculations and Simple Assessment notices (PA302) from late September 2026 for tax due on bank and building society interest earned between April 2025 and April 2026. A second notice for the same year may include tax already paid, so the figures should be checked against bank statements before payment.
UK tax return: you must tell HMRC by 5 October or face a penalty for staying quiet
Self-employment above £1,000, rent, savings interest, dividends or money from abroad in 2025/26 means registering for Self Assessment by 5 October 2026. The return comes later — 31 October on paper, 31 January online. The penalty for registering late is calculated on the tax you still owe and lands separately from late filing penalties.