Is There Income Tax in Idaho? Rates, Credits, and Filing

Yes, Idaho has a state income tax. It is a flat 5.3 percent on individual taxable income above a small zero-bracket amount, and it applies to full-year residents, part-year residents, and nonresidents who earn money from Idaho sources.¹ The Idaho State Tax Commission administers the tax under Title 63, Chapter 30 of the Idaho Code.²

The Rate and What You’ll Actually Owe

Idaho uses a single rate rather than graduated brackets. For the 2025 tax year (filed in 2026), the first slice of taxable income is taxed at zero percent, and everything above that is taxed at 5.3 percent.³

The zero-bracket amount for 2025 is $4,811 for single filers and $9,622 for married couples filing jointly. So a single filer with $50,000 of Idaho taxable income pays 5.3 percent on the $45,189 above the zero bracket, which comes to roughly $2,395.³

Idaho taxable income starts with your federal adjusted gross income and is then adjusted by Idaho-specific additions and subtractions. The federal standard deduction is baked into that starting figure, so there is no separate state standard deduction to claim.

Who Has to File

Whether you have to file depends on where you lived during the year and how much you made.²

Full-Year Residents

If you lived in Idaho all year, you file once your gross income reaches the threshold for your filing status and age. For the 2025 tax year:²

Single, under 65: $15,000
Single, 65 or older: $17,000
Married filing jointly, both under 65: $30,000
Married filing jointly, one or both 65 or older: $31,600 to $33,200
Married filing separately, any age: $5
Head of household, under 65: $22,500
Head of household, 65 or older: $24,500

Residents are taxed on all income, including money earned outside Idaho.

Part-Year Residents

If you moved into or out of Idaho during the year, you file once your combined gross income exceeds $2,500. That total includes everything you earned from any source while you were a resident, plus any Idaho-source income you earned while you were a nonresident.

Nonresidents

If you never lived in Idaho but earned money from Idaho sources, such as wages from an Idaho employer, rent from Idaho property, or gains from selling Idaho real estate, you file when that Idaho-source income exceeds $2,500. Only your Idaho-source income is taxed.

Active-Duty Military

Idaho residents on active duty outside the state for 120 or more consecutive days are exempt from Idaho income tax on their military pay. They still file Form 40 and subtract the qualifying military income.⁴

Income Idaho Doesn’t Tax

Several subtractions can pull your Idaho taxable income below your federal AGI. The ones that matter for most people:

Social Security and Railroad Retirement benefits included in your federal AGI are not taxed by Idaho.⁵
Interest on U.S. Treasury securities and other federal obligations is exempt.
Military retirement pay from the U.S. government is fully subtracted.⁶
Certain Civil Service, Idaho firefighter, and Idaho city police retirement benefits qualify, subject to eligibility dates tied to when the retiree first qualified for the plan. An unremarried surviving spouse of an eligible retiree can claim this at 65, or at 62 if disabled.⁶

Credits and Deductions Worth Knowing

Idaho Food Tax Credit

The food tax credit (once called the grocery credit) refunds some of the sales tax you pay on groceries. For 2025 and beyond, it is $155 per person, with an extra $50 for residents 65 or older, for a total of $205. If you kept your grocery receipts, you can instead claim the actual Idaho sales tax you paid on food, capped at $250 per person. You can file for this credit even if your income is below the filing threshold.⁷

IDeal 529 Contributions

Contributions to an Idaho IDeal 529 college savings account are deductible up to $6,000 for individual filers or $12,000 for married couples filing jointly, claimed on Form 39, Line 14.⁸

Health Insurance Premiums

You can subtract health insurance and long-term care premiums you paid out of pocket, but only amounts that were not already deducted or paid with pre-tax money. Premiums paid through a cafeteria plan, drawn from a medical savings account, or deducted as business expenses do not qualify.⁹

Deadlines, Extensions, and What Late Costs

Idaho individual returns for the 2025 tax year are due April 15, 2026. If you can’t file by then, Idaho grants an automatic six-month extension with no application required, pushing the filing deadline to October 15, 2026.¹⁰

The extension covers filing, not paying. Any tax you owe is still due April 15, and interest runs on unpaid balances from that date regardless of the extension.

Idaho does not require quarterly estimated payments from individuals. You can make voluntary payments through the year to shrink an April balance, which helps if you have substantial self-employment or investment income.¹¹

If you miss a deadline, the penalty depends on which one:¹²

Late filing without a valid extension: 5 percent of unpaid tax per month, up to 25 percent
No valid extension and no payment by the due date: 2 percent per month from the original due date
Filed on time but paid late: 0.5 percent per month, up to 25 percent
Substantially understating the tax owed: 10 percent
Fraudulent return: 50 percent

Any penalty is at least $10. On top of the penalty, interest runs on unpaid balances at 6 percent per year for 2026 (0.5 percent per month), starting from the original due date even if you have an extension.¹³

How to File and Pay

Full-year residents file Form 40. Part-year residents and nonresidents file Form 43. If you amend your federal return, attach a copy of your federal Form 1040-X when you file the matching Idaho amended return.¹⁰

Idaho offers free e-filing for qualifying taxpayers and accepts returns filed through approved commercial tax software. Paper returns can be mailed to the address printed on your form.¹⁴

Payments go through the Idaho Taxpayer Access Point (TAP) online portal. Paying from a bank account is free; debit or credit cards carry a processing fee. If you prefer to mail a check, you can generate a payment voucher in TAP, print it, and send it with your check.¹⁵

1
Idaho State Legislature. Idaho Code 63-3024 – Individuals Tax and Tax Rate
2
Idaho State Tax Commission. Individual Income Tax Basics
3
Idaho State Tax Commission. Individual Income Tax Rate Schedule
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Idaho State Tax Commission. Income Tax for Active-Duty Military
5
Legal Information Institute. Idaho Admin Code r 35.01.01.254 – Nonresident and Part-Year Resident Returns
6
Legal Information Institute. Idaho Admin Code r 35.01.01.130 – Deduction of Certain Retirement Benefits
7
Idaho State Tax Commission. Idaho Food Tax Credit
8
Idaho College Savings Program. Tax Time
9
Legal Information Institute. Idaho Admin Code r 35.01.01.193 – Health Insurance Costs and Long-Term Care Insurance
10
Idaho State Tax Commission. Individual Income Tax Filing and Paying
11
Idaho State Tax Commission. Avoid a Tax Debt
12
Idaho State Tax Commission. Interest and Penalties
13
Idaho State Tax Commission. Interest Rates
14
Idaho State Tax Commission. E-File
15
Idaho State Tax Commission. Filing and Paying in TAP