State Income Tax

Income Tax in Idaho: Complete Guide 2026

Updated 2026-03-11

Data Notice: Figures, rates, and statistics cited in this article are based on the most recent available data at time of writing and may reflect projections or prior-year figures. Always verify current numbers with official sources before making financial, medical, or educational decisions.

Income Tax in Idaho: Complete Guide 2026

Tax information is for educational purposes only and does not constitute tax advice. Consult a licensed tax professional for your specific situation.

Idaho transitioned to a flat individual income tax rate in recent years, simplifying what was previously a multi-bracket graduated system. For 2026, the state imposes a flat rate of approximately ~5.695% on all taxable income above the standard deduction and exemption amounts. This change was part of a broader tax reform effort by the Idaho Legislature aimed at making the state more competitive with neighboring states like Wyoming and Nevada, which have no income tax at all. Idaho also provides a generous grocery tax credit that partially offsets the state sales tax on food.

Idaho Income Tax Rates (2026)

ComponentRate / Amount
Flat income tax rate~5.695%
Standard deduction (single)~$14,600
Standard deduction (married filing jointly)~$29,200
Personal exemption credit~$60 per person

Idaho conforms closely to federal taxable income as the starting point, then applies Idaho-specific adjustments, additions, and subtractions to arrive at Idaho taxable income.

How Idaho Income Tax Works

Flat Rate Structure

Idaho’s flat rate of ~5.695% applies uniformly to all taxable income after the standard deduction and adjustments. This simplifies tax planning considerably compared to the former graduated system, which had rates ranging from ~1% to ~6.5%.

Federal Conformity

Idaho uses federal taxable income as the starting point for computing state tax. This means most federal deductions, including the standard deduction, flow through to your Idaho return. Key Idaho-specific modifications include:

  • Addition: State and local tax refunds included in federal income
  • Subtraction: Interest from U.S. government obligations
  • Subtraction: Idaho capital gains deduction (up to ~60% of qualifying Idaho-source capital gains, with a maximum deduction of ~$15,000 for individuals)

Retirement Income

  • Social Security: Not taxed by Idaho
  • Pension and retirement income: Taxable, but filers age 65 or older (or disabled) may claim a deduction of up to ~$46,044 for joint filers from qualifying retirement benefits, reduced by Social Security and Railroad Retirement benefits received
  • Military retirement: Subject to the same retirement benefits deduction

Tax Credits

  1. Grocery credit: ~$120 per person (filers and dependents) to offset sales tax on groceries, with no income limit for residents
  2. Child tax credit: Idaho offers a nonrefundable credit for qualifying children
  3. Earned income credit: Not offered at the state level as of 2026
  4. Investment tax credit: For qualifying investments in Idaho businesses
  5. Technology credit: For research and development conducted in Idaho

Who Must File in Idaho

You must file an Idaho income tax return if:

  • You are a full-year resident with gross income exceeding ~$14,600 (single) or ~$29,200 (married filing jointly)
  • You are a part-year resident or nonresident with Idaho-source income exceeding ~$2,500
  • You want to claim the grocery tax credit

Idaho uses Form 40 for residents and Form 43 for part-year and nonresident filers. The deadline is April 15.

Comparison to National Average

StateIncome Tax RateStructure
Idaho~5.695%Flat
Utah~4.65%Flat
Montana~5.90% (top)Graduated
Oregon~9.90% (top)Graduated
Wyoming~0%No income tax
National average~4.60%Varies

Idaho’s flat rate is above the national average but below the rates of its western neighbors Oregon and Montana. The state’s competitive cost of living and absence of local income taxes help offset the rate differential compared to no-income-tax states like Wyoming and Nevada.

Tips for Minimizing Idaho Income Tax

  1. Claim the grocery credit for every household member. At ~$120 per person, a family of four receives ~$480 in direct tax relief, regardless of income level.

  2. Use the capital gains deduction. If you sell qualifying Idaho property, you may deduct up to ~60% of the gain (capped at ~$15,000), significantly reducing the effective tax on the transaction.

  3. Maximize the retirement benefits deduction. If you are 65 or older, the retirement benefits deduction of up to ~$46,044 for joint filers can eliminate state tax on substantial retirement income.

  4. Contribute to retirement accounts. Because Idaho starts with federal taxable income, 401(k) and traditional IRA contributions reduce your Idaho tax base automatically.

  5. Consider the Idaho 529 deduction. Contributions to the Idaho College Savings (IDeal) program are deductible up to ~$6,000 per contributor per year.

  6. Track Idaho-source capital gains separately. The capital gains deduction only applies to gains from Idaho property held for at least 12 months. Keeping detailed records is essential.

  7. File electronically for faster refunds. Idaho Tax Commission processes e-filed returns significantly faster than paper returns, especially for refunds including the grocery credit.

Key Takeaways

  • Idaho levies a flat income tax of ~5.695% on all taxable income after the standard deduction
  • The state conforms to federal taxable income as the starting point, simplifying calculations
  • A generous grocery credit of ~$120 per person offsets sales tax on food purchases
  • The capital gains deduction allows up to ~60% exclusion on qualifying Idaho property gains (maximum ~$15,000)
  • Retirees 65+ can deduct up to ~$46,044 of retirement income for joint filers
  • Social Security benefits are fully exempt from Idaho income tax

Next Steps