Disclaimer: This calculator gives you an estimate based on tax rates and details found online. These rates may change over time. For the most accurate and up-to-date information, please check the official IRS website and your state’s tax website. Always talk to a tax expert for advice about your personal tax situation.
How We Calculate the Result
To estimate your Idaho income tax, we start with your total household income. From that, we subtract any contributions you made to a 401(k), IRA, itemized deductions, and personal exemptions (if you entered any). This gives us your taxable income. Idaho has a flat income tax rate of 5.8%, which means all of your taxable income is taxed at that same rate. After calculating the tax owed, we show your effective tax rate (how much of your total income goes to Idaho income tax).
We also check your age and filing status to tell you whether you’re required to file a federal tax return, using the latest IRS thresholds. This calculator gives you a helpful estimate, but for exact numbers or complex situations, consult a tax professional.
About Idaho Income Tax
Idaho uses a flat income tax system, meaning every taxpayer pays the same tax rate on their taxable income — 5.8% as of 2025. Unlike progressive tax systems, this doesn’t change based on how much you earn. Instead, after your income is adjusted with deductions and exemptions, the remaining amount is taxed at a flat rate.
Idaho allows deductions like 401(k) and IRA contributions, and offers a standard deduction and personal exemptions that help lower your taxable income. These benefits make a difference for families, seniors, and people with retirement savings.
Income tax is paid annually, and most people file their returns in April. Whether you’re single, married, or filing as head of household, this tool can help you estimate your Idaho income tax quickly and easily.
Frequently Asked Questions
What is the income tax rate in Idaho?
Idaho has a flat income tax rate of 5.8% on taxable income. This means everyone pays the same percentage, whether you earn a small or large income. The amount you pay depends on your taxable income after deductions and exemptions.
When do singles start paying Idaho income tax?
A single person under 65 must file if their income is at least $14,600. If they are 65 or older, the threshold is $16,550. This doesn’t mean you’ll owe tax — it just means you’re required to file a federal return and possibly a state return.
When do married filers start paying Idaho income tax?
Married couples filing jointly need to file if their income is at least $29,200 (both under 65), $30,750 (one spouse 65+), or $32,300 (both 65+). This is based on federal filing thresholds. Idaho income tax applies based on your final taxable income.
What deductions can reduce Idaho taxable income?
You can reduce your taxable income with 401(k) contributions, IRA contributions, itemized deductions (if greater than the standard), and personal exemptions. These reduce how much income is taxed at the 5.8% rate.
Do I need to file Idaho taxes if I live elsewhere?
If you earned income from Idaho sources — such as a job, rental, or business — you may need to file an Idaho non-resident return. Even if you live out of state, you must report Idaho income and may owe tax on it.