Idaho Personal Tax Extension 2026: 2025 Tax-Year Filing Guide
Individual Income Tax · Form 40
Idaho generally grants an automatic extension for individual returns. Idaho’s automatic extension depends on meeting its payment threshold. For federal details, see our federal tax extension resources.
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✓ Secure e-filing✓ 24/7 filingIdaho generally grants an automatic extension for individual returns. Idaho’s automatic extension depends on meeting its payment threshold.
Last updated: September 12, 2026Idaho Personal Tax Extension: Filing Details
Idaho generally grants an automatic extension for individual returns. Idaho’s automatic extension depends on meeting its payment threshold.
Quick Reference: Deadlines and Forms
Use this summary to confirm Idaho filing deadlines, forms, and payment requirements.
| Item | Idaho personal return | Deadline or method |
|---|---|---|
| Original deadline | Form 40 | April 15, 2026 |
| Extended deadline | Automatic | October 15, 2026 |
| Return form | Form 40 | Use the current form |
| Payment | Form 51 | Due April 15, 2026 |
Frequently Asked Questions
Answers about Idaho personal tax extensions.
Yes. Idaho generally provides an automatic six-month extension when its payment requirement is met.
Pay at least 80% of current-year tax or 100% of prior-year tax by April 15, 2026.
The extended filing deadline is October 15, 2026.
Check the Idaho Tax Commission for current forms, instructions, and payment rules.