Idaho Income Tax Calculator

How to Use This Idaho Income Tax Calculator

This Idaho income tax calculator estimates your annual ID state and federal tax liability for 2025 and 2026. Enter your gross wages, filing status, and any deductions above. Idaho applies a flat 5.3% rate after the state standard deduction — identical in amount to the federal standard deduction. For per-paycheck withholding estimates, use the Idaho paycheck calculator.

How Idaho State Income Tax Works

Idaho simplified its income tax structure in 2023, moving from a multi-bracket progressive system to a single flat rate. The flat rate has been reduced each year since:

• 2023: 5.8%
• 2024: 5.695%
• 2026: 5.3%

The flat structure means every Idaho taxpayer pays the same marginal rate, regardless of income. A $40,000 earner and a $400,000 earner both pay 5.3% on their taxable income above the standard deduction. There are no brackets, no phase-outs, and no surtaxes.

Idaho's standard deduction matches the federal amounts — $14,600 for single filers and $29,200 for married filing jointly in 2026. This is among the most generous in the country; by comparison, Kansas allows only $3,500 (single) and Hawaii only $2,200 (single).

Step-by-Step Example — $90,000 Idaho Single Filer (2026)

Full annual tax calculation for a single Idaho resident earning $90,000:

1. Gross wages: $90,000
2. Federal standard deduction: −$16,100 → federal taxable income: $73,900
3. Federal income tax (10%–22% brackets): ≈ $12,140
4. FICA: $90,000 × 7.65% = $6,885
5. Idaho standard deduction: −$14,600 → Idaho taxable income: $75,400
6. Idaho income tax at 5.3%: $75,400 × 0.053 = $3,996
7. Total taxes: $12,140 + $6,885 + $3,996 = $23,021
8. Annual net income: $90,000 − $23,021 = $66,979

Idaho vs Neighboring States

Idaho sits among a mixed group of neighbors for state income tax. Washington and Nevada levy no state income tax. Utah has a comparable 4.65% flat rate. Oregon is significantly higher with progressive brackets reaching 9.9% for higher earners. A $90,000 single filer pays roughly $4,000 in Idaho state tax vs. about $7,400 in Oregon. Idaho's standard deduction also compares favorably — the $14,600 single deduction is roughly 6× larger than Kansas's $3,500. Use the general income tax calculator to compare Idaho with any other state side by side.

How to Reduce Your Idaho Annual Tax Liability

• Maximize traditional 401(k) contributions — the 2026 limit is $23,500 ($31,000 if age 50+). At 5.3% Idaho + 22% federal = 27.3% combined marginal rate, every $1,000 contributed saves $273.
• Contribute to an HSA — $4,300 (self-only) or $8,550 (family) in 2026. HSA reduces both federal and Idaho taxable income.
• Idaho College Savings Program (IDeal 529) — contributions up to $6,000 (single) or $12,000 (MFJ) per year are deductible from Idaho taxable income. At 5.3%, $6,000 saves up to $318 in Idaho state tax annually.
• Contribute to an IRA — traditional IRA contributions (up to $7,000 or $8,000 age 50+) reduce Idaho taxable income if you qualify for the deduction.
• Itemize Idaho deductions when beneficial — taxpayers who itemize for federal purposes may itemize for Idaho as well. If mortgage interest, property taxes, and charitable contributions exceed $14,600 (single), itemizing reduces Idaho taxable income below the standard deduction floor.

Idaho's No-Local-Tax Advantage

Unlike states such as Ohio (600+ municipal tax authorities) or Maryland (county piggyback taxes), Idaho levies no local income tax in any city or county. Boise, Nampa, Idaho Falls, and Pocatello residents pay only the flat 5.3% state rate on top of federal tax. For someone earning $90,000, this saves roughly $900–$2,250 per year compared to a worker in a state with a 1%–2.5% local tax. Use the Idaho paycheck calculator to see the per-paycheck impact alongside your federal withholding.

Retirement Income and Idaho Taxes

Idaho does not provide a blanket exemption for retirement income — most retirement distributions are taxable at the flat 5.3% rate. However, Idaho does have one significant retirement benefit for older residents:

• Social Security benefits: Idaho follows the federal treatment of Social Security. If your Social Security benefits are included in your federal adjusted gross income (because your combined income exceeds the federal thresholds — $25,000 single / $32,000 MFJ), that same amount is also included in Idaho taxable income. Idaho provides no separate Social Security exemption at the state level, unlike most US states.
• Retirement Benefits Deduction (age 65+): Idaho residents age 65 and older may deduct up to $38,480 (single filers) or $57,720 (married filing jointly) of qualifying retirement income from Idaho taxable income. This deduction covers pension income, 401(k) distributions, IRA withdrawals, and Social Security benefits from qualified retirement plans. At 5.3%, the maximum single deduction saves up to $2,040 in Idaho state tax.
• 401(k) and IRA distributions (under 65): Fully taxable in Idaho at the flat 5.3% rate. There is no early distribution special treatment at the state level — Idaho mirrors federal taxation of pre-tax retirement account withdrawals.
• Pension income: Private and government pension distributions are taxable in Idaho for residents under 65. Residents 65+ may shelter up to the $38,480 / $57,720 limit through the retirement benefits deduction.
• Military retirement pay: Idaho does not fully exempt military retirement income; it is included in the retirement benefits deduction pool for qualifying taxpayers 65+, but is otherwise taxed at the flat rate.

Idaho retirees 65+ with combined retirement income below $38,480 (single) effectively pay zero Idaho income tax on that income after the deduction — a significant benefit for those with modest retirement income. Higher-income retirees will owe Idaho tax on amounts above the deduction limit.

Idaho Tax Credits and Deductions

Beyond the standard deduction and retirement deductions described above, Idaho offers several additional credits and deductions:

• Idaho Earned Income Tax Credit (EITC): Idaho provides a state EITC equal to 10% of the federal EITC. For qualifying lower-income earners who receive a $2,500 federal EITC, Idaho adds $250 as a credit against Idaho income tax owed. The Idaho EITC is non-refundable — it can reduce your Idaho tax to zero but does not generate a refund.
• IDeal 529 College Savings Deduction:Contributions to Idaho's IDeal 529 plan (administered by Ascensus) are deductible from Idaho taxable income up to $6,000 per year for single filers and $12,000 for married filing jointly. At 5.3%, the full $6,000 single deduction saves $318 in Idaho state tax annually. This is among the most generous 529 state deduction limits relative to Idaho's flat rate.
• Charitable Contributions: Idaho allows itemized deductions following federal rules. Taxpayers who itemize for federal purposes can also itemize for Idaho. Since Idaho uses the same standard deduction as the federal standard deduction ($14,600 single), itemizing only makes sense for the same filers who itemize federally.
• Credit for Taxes Paid to Other States: Idaho residents who earn income in another state may claim a credit for taxes paid to that other state, preventing full double-taxation on the same income.

Idaho's individual income tax return is Form 40. The filing deadline is April 15 (same as federal), with an automatic six-month extension to October 15. An extension to file does not extend the time to pay — interest and penalties accrue on unpaid balances after April 15.

Tax Disclaimer

This calculator provides estimates for informational purposes only. It is not tax advice. Idaho state tax rates, standard deduction amounts, and federal rules change each year. Results reflect 2025 and 2026 tax-year parameters. Consult a qualified tax professional or CPA for guidance on your specific situation.