Idaho has a state income tax, and it applies to most types of income you earn

Yes, Idaho taxes your income at the state level. If you live in Idaho or earn income there, you will owe state income tax on wages, self-employment income, investment gains, and most other sources. Idaho's state income tax is separate from federal income tax — you file both, and the state keeps what you owe to Idaho.

Idaho's income tax rates range from 1% to 5.8%, depending on how much you earn. The more you make, the higher your rate, which is called a progressive tax system. This is different from a flat tax, where everyone pays the same percentage regardless of income.

You will also owe FICA taxes (Social Security and Medicare) if you work, and you may owe federal income tax. These are separate from Idaho's state tax and go to the federal government, not Idaho.

Key Takeaways

  • Idaho's state income tax rates run from 1% to 5.8% depending on your income level, and the rate increases as you earn more.
  • You file Idaho state taxes on Form 40, which is separate from your federal return, and both are due by April 15 unless you request an extension.
  • Idaho taxes wages, self-employment income, interest, dividends, and capital gains, though long-term capital gains receive preferential treatment at the federal level.
  • If you move to Idaho from another state, you may owe taxes to both states for the year you move, depending on when you establish residency.
  • Idaho offers a standard deduction and personal exemptions that reduce your taxable income, similar to the federal system.

How Idaho's Tax Brackets Work

Idaho uses tax brackets, which means different portions of your income are taxed at different rates. You do not pay 5.8% on all your income if you reach the top bracket — you pay the lower rates on the lower portions first. For example, if you are single, your first portion of income is taxed at 1%, the next portion at 2%, and so on, until you reach the 5.8% bracket for your highest earnings.

The exact dollar amounts where each bracket begins change every year because Idaho adjusts them for inflation. The Idaho State Tax Commission publishes the current year's brackets on their website each January. Your income level determines which brackets explore to you, and your filing status (single, married filing jointly, head of household) affects where each bracket starts and stops.

Because brackets shift annually, your tax bill can change even if your income stays the same. A raise that pushes you into a higher bracket means only the income above that threshold is taxed at the new rate, not your entire income.

What Income Types Idaho Taxes

Idaho taxes most forms of income the same way the federal government does. Wages from your job, tips, bonuses, and self-employment income all count. If you own a business, you report your net profit (income minus business expenses) on your Idaho return. Interest from savings accounts and bonds, dividends from stocks, and capital gains from selling investments are also taxable in Idaho.

Long-term capital gains — profits from selling an asset you held for more than one year — receive a federal tax break: you pay a lower rate than ordinary income. Idaho follows the federal treatment, so your state tax on long-term gains is also lower than on wages or short-term gains. Short-term capital gains (from assets held one year or less) are taxed as ordinary income at your regular rate.

Some income types are not taxed by Idaho. Social Security benefits are generally not taxable in Idaho, even if they are taxable at the federal level. Certain retirement distributions and municipal bond interest may also escape Idaho tax. The rules vary depending on your age and income level, so check the Idaho State Tax Commission website or a tax professional if you receive these types of income.

Filing Your Idaho State Return

You file your Idaho state tax return on Form 40 (or Form 40-N if you are a nonresident). This form is separate from your federal return, even though both are due on the same date: April 15 of the year after the tax year ends. If you need more time, you can request an extension, which gives you until October 15 to file, though taxes owed are still due by April 15.

Idaho allows you to file electronically through approved software or through a tax professional. You can also file by mail if you prefer, though electronic filing is faster and reduces errors. When you file, you report your income, claim deductions and exemptions, and calculate what you owe or what refund you should receive.

If you are a resident of Idaho, you report all your income on Form 40, including income earned outside the state. If you are a nonresident who earned income in Idaho, you file Form 40-N and report only the income you earned in Idaho. Some people are part-year residents (they moved to or from Idaho during the year), and they file a special return that splits their income between resident and nonresident portions.

Deductions and Exemptions That Lower Your Tax

Idaho offers a standard deduction, which is a flat amount you can subtract from your income before calculating tax. The standard deduction amount depends on your filing status and age. If you are 65 or older, you get a higher standard deduction. You can also claim an exemption for yourself and each dependent, which further reduces your taxable income.

Alternatively, you can itemize deductions if your total itemized deductions exceed the standard deduction. Itemized deductions include mortgage interest, property taxes, charitable donations, and medical expenses above a certain threshold. Most people use the standard deduction because it is simpler and often larger, but itemizing can save money if you have significant deductible expenses.

Idaho also offers tax credits for certain situations, such as having dependent children, earning low income, or paying for education. Credits are different from deductions: a credit directly reduces your tax bill dollar-for-dollar, while a deduction reduces the income that is taxed. A $1,000 credit saves you $1,000 in tax; a $1,000 deduction saves you roughly $58 in tax (at the 5.8% rate), depending on your bracket.

Moving to Idaho and Owing Taxes to Two States

If you move to Idaho from another state during the year, you may owe income tax to both Idaho and your former state for the same year. The state you lived in for part of the year may claim you as a resident for that period, and Idaho will claim you as a resident for the period you lived there. Both states tax the income you earned while you were a resident.

To avoid paying tax twice on the same income, most states offer a credit for taxes paid to another state. If you paid income tax to your former state, you can claim a credit on your Idaho return for those taxes, which reduces what you owe Idaho. However, the credit is limited to the amount of Idaho tax you owe, so it does not create a refund if the other state's tax was higher.

The key to managing this situation is establishing your residency date clearly. Your residency date is usually the day you move to Idaho with the intent to stay. Keep documentation such as a lease, utility bills, or a driver's license change to prove when you became an Idaho resident. This date determines how you split your income between the two states.

Self-Employment Income and Idaho Taxes

If you are self-employed, you owe Idaho state income tax on your net business profit, just as you owe federal income tax. Your net profit is your business income minus your business expenses. You report this on your Idaho return using the same net profit figure you calculated for your federal return (usually on Schedule C).

Self-employed people also owe self-employment tax, which is the self-employed version of FICA. Self-employment tax covers Social Security and Medicare and is calculated separately from income tax. Idaho does not tax self-employment tax itself, but the federal government does, and you pay it in addition to both federal and state income tax.

If your business has employees, you must withhold Idaho state income tax from their paychecks and send it to the state, just as you do with federal withholding. You also withhold FICA taxes. These are employer responsibilities, separate from your own tax bill as the business owner.

Frequently Asked Questions

Do I have to file an Idaho return if I only lived there part of the year?

Yes, if you earned income while you were an Idaho resident, you must file. You report only the income you earned during the months you were a resident on Form 40-NR (part-year resident). Your former state may also require a return for the months you lived there.

Does Idaho tax retirement income differently?

Social Security is generally not taxable in Idaho. Distributions from traditional IRAs and 401(k)s are taxable as ordinary income. Some military pensions and federal employee pensions receive special treatment, so check with the Idaho State Tax Commission if you receive pension income.

What if I earned income in Idaho but do not live there?

You file Form 40-N (nonresident return) and report only the income you earned in Idaho. You still owe Idaho tax on that income, but you do not report income from other states. Your home state may also tax you on the same income, so you can claim a credit for Idaho taxes paid.

Can I get an extension to file my Idaho return?

Yes, you can request an extension that moves your filing important date to October 15. However, any taxes you owe are still due by April 15. If you do not pay by April 15, you will owe interest and penalties on the unpaid amount, even if you file the return later.

How do I know if I owe Idaho tax?

You owe Idaho tax if you are a resident and earned any taxable income, or if you are a nonresident who earned income in Idaho. The amount depends on your income level, filing status, and deductions. Use the Idaho State Tax Commission's tax tables or software to estimate what you owe.