2025 US Income Tax – Important Dates for 2026

✅ 15 April 2026

• Initial due date for 2025 Individual Income Tax Returns (Form 1040) and State Tax Returns for taxpayers residing in the US
  
  
• All outstanding tax due for the 2025 calendar year must be paid by this date regardless of residence; extensions to file do not extend time to pay and interest on unpaid tax begins from this date.
  
  
• Form 4868 may be submitted to request a six‑month extension to file to 15 October 2026.
  
  
• Most State Tax Return extensions must be filed by this date.​
  
  
• Initial due date for 2025 Estate, Domestic Trust, and Partnership Tax Returns (for calendar‑year filers).​
  
  
• First estimated tax payment due for 2026 (Individual, Trust, Estate, and Corporate).​
  
  
• Due date for filing FinCEN Form 114, “Report of Foreign Bank and Financial Accounts” (FBAR) for the 2025 calendar year, with an automatic extension to 15 October 2026; this is separate from tax returns.​
  
  
  

✅ 15 June 2026

• Automatic extended due date for 2025 Individual Income Tax Returns for taxpayers living outside the US on 15 April 2026; interest generally accrues on unpaid taxes from 15 April 2026 until settled.​
  
  
• Form 4868 may be submitted by this date by qualifying taxpayers abroad to request a further four‑month extension to 15 October 2026.​
  
  
• State Tax Return extensions (where applicable) must generally be submitted by this date for taxpayers residing outside the US.​
  
  
• Second estimated tax payment due for 2026 (Individual, Trust, Estate, and Corporate).
  
  
  

✅ 15 July 2026

• Due date for extended 2025 Estate, Domestic Trust, and Partnership Tax Returns, where a three‑month extension from April has been obtained.​

✅ 15 September 2026

• Final due date for extended 2025 calendar‑year S corporation and partnership income tax returns (Forms 1120‑S and 1065).​
  
  
• Final due date for extended 2025 Foreign Trust Tax Returns (Form 3520‑A) for calendar‑year trusts where a six‑month extension was filed.​
  
  
• Third estimated tax payment due for 2026 (Individual, Trust, Estate, and Corporate).​
  
  
  

✅ 15 October 2026

• Final due date for extended 2025 Individual Income Tax Returns for taxpayers residing in the US.​
  
  
• Final due date for extended 2025 Estate and Domestic Trust Income Tax Returns, where a valid extension is in place.​
  
  
• Final due date for extended 2025 calendar‑year C corporation income tax returns (Form 1120).​
  
  
• Final due date for filing FinCEN Form 114 (FBAR) for 2025 under the automatic extension.​
  
  
• Due date for individual extension applications requesting further extension to 15 December 2026 for qualifying taxpayers residing outside the US on 15 April 2026 (with a timely filed initial extension through 15 October 2026).​
  
  
  

✅ 15 November 2026

• In limited cases involving special trustee or substitute‑filer arrangements, certain foreign trust filings may fall around this date; this is not a standard IRS deadline.
  
  
  

✅ 15 December 2026

• Fourth and final estimated tax payment due for 2026 (Corporations only) for calendar‑year C corporations.​
  
  
  

✅ 15 January 2027

• Fourth and final estimated tax payment due for 2026 (Individuals, Trusts, and Estates).​
  
  
  

For the comprehensive view of all of our US Tax Services, visit the US Private Client page.

📞 If assistance is needed navigating these deadlines, please reach out for expert support using the form at the bottom of the page.