Idaho simplified its income tax system in 2023 by switching from a graduated rate structure to a flat 5.695% rate, making it one of the straightforward states to calculate your state tax bill.
Quick answer: Every Idaho resident pays 5.695% on taxable income. Social Security is fully exempt. The standard deduction mirrors the federal amount ($15,000 single / $30,000 married for 2026).
Idaho Income Tax Rate 2026
| Filing Status | Rate |
|---|---|
| Single | 5.695% |
| Married Filing Jointly | 5.695% |
| Head of Household | 5.695% |
| Married Filing Separately | 5.695% |
Idaho’s flat tax means there is no bracket math — you multiply your taxable income (after deductions and exemptions) by 5.695%.
Idaho Standard Deduction and Exemptions
Idaho conforms to the federal standard deduction for 2026:
| Filing Status | Standard Deduction |
|---|---|
| Single | $15,000 |
| Married Filing Jointly | $30,000 |
| Head of Household | $22,500 |
| Married Filing Separately | $15,000 |
Idaho also allows a personal exemption credit of $113 per person (taxpayer, spouse, and each dependent). This credit is subtracted directly from your Idaho tax owed — not from your income.
Worked Example — Idaho Tax on $75,000 Income (Single)
| Item | Amount |
|---|---|
| Gross income | $75,000 |
| Federal standard deduction | −$15,000 |
| Idaho taxable income | $60,000 |
| Idaho flat tax (5.695%) | $3,417 |
| Personal exemption credit | −$113 |
| Idaho tax owed | $3,304 |
| Effective Idaho rate | 4.4% |
The effective rate is lower than 5.695% because the standard deduction eliminates the tax on the first $15,000 of income.
What Idaho Does and Doesn’t Tax
Exempt from Idaho Income Tax
- Social Security benefits — fully exempt regardless of income
- Roth IRA qualified distributions — no Idaho tax (follows federal treatment)
- U.S. military active duty pay — exempt for Idaho residents stationed outside Idaho
Taxed by Idaho
- Wages, salaries, and self-employment income
- 401(k) and traditional IRA withdrawals
- Pension and annuity income (no special exemption)
- Capital gains (treated the same as ordinary income)
- Business income
Idaho Retirement Tax Considerations
Idaho does not have a blanket retirement income exemption, but the Social Security exemption is significant. A retiree living entirely on Social Security owes zero Idaho state income tax.
For retirees drawing from 401(k)s, IRAs, or pensions: Idaho taxes these at the flat 5.695% rate. Idaho does allow a retirement income deduction for taxpayers 65 and older or those who are disabled — up to $4,489 for single filers and $8,978 for married couples, claimed on Form 39R.
Who Must File an Idaho Return
You must file an Idaho income tax return if:
- You are a full-year resident and your gross income exceeds the standard deduction plus exemptions
- You are a part-year resident with Idaho-source income
- You are a nonresident with any Idaho-source income (wages earned in Idaho, rental property in Idaho, etc.)
For most single Idahoans, the filing threshold is approximately $15,113 (standard deduction + personal exemption credit equivalent).
Idaho Tax Payment and Filing
- Filing deadline: April 15, 2026
- Extension to file: Automatic with federal extension (Form 51 if filing state-only extension) — but tax is still due by April 15
- Estimated tax payments: Required quarterly if you expect to owe more than $500 in Idaho tax
- E-file: Available through Idaho’s Taxpayer Access Point (TAP) at tax.idaho.gov
- Paper filing: Form 40 (residents); Form 43 (part-year/nonresident)
Idaho vs. Neighboring States
| State | Income Tax |
|---|---|
| Idaho | 5.695% flat |
| Washington | 0% (no income tax) |
| Oregon | 8.75%–9.9% graduated |
| Nevada | 0% (no income tax) |
| Montana | 4.7%–5.9% graduated |
| Wyoming | 0% (no income tax) |
| Utah | 4.65% flat |
Idaho’s flat rate is notably higher than flat-rate neighbors like Utah. The proximity to no-income-tax states like Washington and Nevada is a driver of cross-border migration patterns.
Related Guides
- 9 States With No Income Tax 2026
- Federal Income Tax Brackets 2026
- State Income Tax Rates 2026 — All 50 States
- How to Lower Your Taxable Income
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