The Idaho tax code applies a 5.3 percent flat income tax to individuals and corporations, a 6 percent statewide sales tax that includes groceries, and locally assessed property taxes administered county by county. The Idaho State Tax Commission handles income and sales tax; county assessors handle property valuations. A per-person grocery credit offsets some of the sales tax on food, and homeowners who live in their property can shelter a chunk of its value from property tax.
Individual Income Tax
Idaho taxes individuals, trusts, and estates at a flat 5.3 percent on taxable income above a built-in zero bracket. For single filers, the first $4,811 is taxed at zero and everything above it at 5.3 percent. Married couples filing jointly get a zero bracket on the first $9,622.1Idaho State Tax Commission. Individual Income Tax Rate Schedule The rate applies to Idaho taxable income, which begins with your federal adjusted gross income and is then adjusted by state-specific additions and subtractions.2Idaho State Legislature. Idaho Code 63-3024 – Individuals Tax and Tax on Estates and Trusts
Residents owe tax on their worldwide income. Part-year residents and nonresidents only report income from Idaho sources, such as wages for work performed in the state or profits from Idaho real estate and businesses. Because the state’s calculation starts from your federal return, finish the federal filing first. Most residents file on Form 40.3Idaho State Tax Commission. Form 40 – 2025 Individual Income Tax Return
Business Income Tax
C corporations doing business in Idaho or earning income from Idaho sources pay the same 5.3 percent flat rate. Even a corporation with zero taxable income or an operating loss owes a $20 minimum each year, with an exception for nonproductive mining corporations.4Idaho State Legislature. Idaho Code 63-3025 – Tax on Corporate Income
S corporations and partnerships generally don’t pay entity-level income tax. Their income flows through to the owners, who report it on personal returns. These pass-through entities may still owe the $20 minimum if they’re authorized to do business in Idaho, and they can be required to withhold tax for nonresident members.
Multistate Corporations
If a corporation operates in more than one state, Idaho uses a single sales factor by default: the share of total sales made to Idaho customers determines the portion of income taxable here.5Legal Information Institute. Idaho Admin Code r 35.01.01.310 – Apportionment Utilities and certain regulated industries can elect a traditional three-factor formula instead.
Sales and Use Tax
Idaho’s sales tax is 6 percent on most retail purchases of tangible personal property and certain services. Groceries are taxed at the full rate. Prescription drugs are exempt. Clothing is fully taxable.
Buy something from an out-of-state seller that doesn’t collect Idaho tax, and you owe a 6 percent use tax on that purchase. The rate mirrors the sales tax and exists to keep online and cross-border buying from undercutting local sellers.6Idaho State Legislature. Idaho Code 63-3621 – Imposition and Rate of the Use Tax – Exemptions If you already paid another state’s sales tax on the item, Idaho credits that payment and you only owe the difference when the other state’s rate was lower.
More than twenty Idaho resort cities add a local sales tax on top of the state rate. Ketchum, Sun Valley, McCall, Sandpoint, and Driggs are among them, and each city’s voters approved its tax separately, so the local rate varies.7Idaho State Tax Commission. City Sales Taxes Businesses in those areas collect both portions.
Property Tax
Property tax is handled at the county level. County assessors determine market value each year, and the rate depends on levies from schools, fire districts, cities, and other taxing districts where the property sits. Two statewide programs can lower what a homeowner pays.
Homeowner’s Exemption
Own and occupy a home as your primary residence, and you can exempt up to $125,000 of its assessed value from property tax, or 50 percent of the assessed value, whichever is less.8Idaho State Legislature. Idaho Code 63-602G – Property Exempt From Taxation – Homestead You apply through your county assessor and certify that the home is your primary dwelling and that you haven’t claimed the exemption elsewhere. A mixed-use home office doesn’t disqualify you, but any portion used exclusively for non-residential purposes is excluded.
Property Tax Reduction (Circuit Breaker)
Idaho’s property tax reduction program can cut your bill by $250 to $1,500. For 2025, your total income after deducting medical expenses must be $39,130 or less, and you must fall into at least one eligibility category: age 65 or older, a surviving spouse, blind, disabled as recognized by Social Security, or a veteran with at least a 10 percent service-connected disability, among others.9Idaho State Tax Commission. Property Tax Reduction The window to apply runs from January 1 through April 15 each year.
Appealing an Assessment
If the assessed value looks too high, your first appeal goes to the county Board of Equalization and must be filed by the fourth Monday in June. If that doesn’t resolve it, the next step is the Idaho Board of Tax Appeals or district court. The notice of appeal is filed with the county auditor, not with the Board of Tax Appeals itself.10Idaho Board of Tax Appeals. Idaho Board of Tax Appeals
Credits and Deductions Worth Knowing
Grocery Credit
Because Idaho taxes food, the state offers a grocery credit to offset part of the cost. Most residents qualify for $155 per person in the household. Keep your grocery receipts and submit them, and you can claim up to $250 per person instead. You can claim the credit even if your income is too low to require filing a return.11Idaho State Tax Commission. Idaho Food Tax Credit
IDeal 529 Deduction
Contributions to Idaho’s IDeal 529 college savings plan are deductible from state taxable income. Single or head-of-household filers can deduct up to $6,000 per year; married couples filing jointly can deduct up to $12,000.12Idaho State Tax Commission. IDeal Idaho College Savings Program This is a deduction, not a credit, so the actual tax savings equal the deduction multiplied by the 5.3 percent rate.
Business Credits
Business owners file Form 44 alongside Form 40 to claim business income tax credits, including credits for investment in qualifying property, research activities, and broadband equipment. Credit amounts and qualification rules vary by category. Recaptured credits (for example, when you dispose of qualifying property too early) also run through Form 44.3Idaho State Tax Commission. Form 40 – 2025 Individual Income Tax Return
Filing, Paying, and Deadlines
Idaho income tax returns for the 2025 tax year are due April 15, 2026.13Idaho State Tax Commission. Individual Income Tax Filing and Paying Any tax you owe is due by the same date even if you file for an extension. An extension buys time to file, not time to pay.
The Tax Commission’s Taxpayer Access Point (TAP) is the fastest way to file and pay. Electronic payment options include bank account transfers and credit cards, with a processing fee on card payments from the third-party provider. Paper returns can be mailed using the addresses in the instruction booklet, but they take considerably longer to process.
One quirk: Idaho does not require individuals to make quarterly estimated tax payments the way the IRS does.14Idaho State Tax Commission. Avoid a Tax Debt You can make voluntary payments toward your expected liability any time during the year, which helps if you have significant self-employment or investment income. Waiting until April to pay a large balance means owing interest.
Penalties and Interest
Idaho treats failing to file very differently from failing to pay, and the gap is wide. Miss the filing deadline (including any extension) and the penalty is 5 percent of the unpaid tax for each month the return is late, up to a maximum of 25 percent. File on time but don’t pay what you owe, and the penalty drops to 0.5 percent of the unpaid tax per month.15Idaho State Legislature. Idaho Code 63-3046 Filing a return on time and arranging to pay later is far cheaper than skipping the filing.
Interest accrues on unpaid tax from the original due date until you pay in full, at a rate updated annually based on market conditions. If you can’t pay everything at once, contacting the Tax Commission early gives you the best chance of setting up an installment agreement before collection actions like wage garnishment or a tax lien begin.