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Self Assessment Tax Return Deadline 2025/26
Online Self Assessment tax return deadline for 2025/26 tax year
Deadline
Sunday, 31 January 2027
Who This Applies To
- Self-employed
- Company directors
- Landlords
- Those with untaxed income
What to File
SA100 tax return plus any supplementary pages (employment, self-employment, dividends, capital gains)
How to File
HMRC online, commercial software, or through accountant
Payment Due
Same day - 31 January 2027
Penalties for Missing This Deadline
£100 immediate fine, then daily penalties after 3 months, then percentage of tax owed after 6/12 months
Tax Year: 2025/26
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