Check Idaho tax deadlines for individuals and C Corporations. Confirm due dates, extension rules, and exemptions for S Corps and Partnerships.
Idaho Tax Deadlines at a Glance (2026)
Entity Type | Return Due | Extension Deadline |
|---|---|---|
Individuals | April 15, 2026 | October 15, 2026 |
C Corporations | April 15, 2026 | October 15, 2026 |
S Corporations | March 16, 2026 | September 15, 2026 |
Partnerships | March 16, 2026 | September 15, 2026 |
Businesses
Idaho generally conforms to federal definitions and timing.
Special Entities
Includes nonprofits with unrelated business income and financial institutions.