If you live or work in Boise, here's what you'll pay in Idaho state income tax in 2026. With a flat 5.8% rate, your Idaho state tax is straightforward to calculate. Use the calculator below to estimate your take-home pay.
Idaho has a flat state income tax rate of 5.8%. This means everyone pays the same percentage regardless of income level. Combined with federal graduated brackets, the overall effect is progressive at higher incomes.
Top marginal rate: 5.8%
Tax structure: Flat rate
State capital: Boise
2026 brackets: Flat 5.8% on all income
Boise does not have a local city income tax, so you only pay federal and Idaho state income tax.
As a Boise resident, your total tax burden is federal + Idaho state. Property taxes and sales taxes apply separately.
Generally, you pay state income tax in the state where you live, not where you work. If you commute from another state, you typically pay that state's tax. Some states have reciprocity agreements that simplify this. Idaho has reciprocity agreements with some neighboring states. Check with your employer for specifics.
All Idaho taxable income is taxed at 5.8%, with no graduated brackets. Standard deduction and personal exemptions apply.
For 2026 returns, the Idaho state tax deadline is typically April 15, 2027 (same as federal). Extensions follow federal rules. If you file for an extension federally, you typically get an automatic state extension too.
You can deduct state and local income taxes (SALT) on your federal Schedule A, capped at $10,000 total for state + local + property taxes. This is most useful if you itemize. Most people take the standard deduction and don't get this benefit.
No. If you moved out of Idaho before earning any income, you don't need to file a Idaho return. You'll file in your new state of residence.
Traditional 401(k) and IRA contributions reduce your federal taxable income. Most states (including Idaho) also reduce your state taxable income. The 2026 limit is $24,500 for 401(k) and $7,500 for IRA (with catch-up if 50+).
Health Savings Accounts offer a triple tax advantage: deductible going in, tax-free growth, tax-free for medical. Idaho follows federal HSA rules (contributions are deductible).
If you're in a high tax bracket, deferring bonuses or consulting income to the next year can lower your effective rate. Self-employed? S-Corp election can save self-employment tax.
If you have a mortgage and high property taxes, itemizing may beat the standard deduction. The SALT cap is $10K but most people in Boise benefit when combined with mortgage interest.
⚠️ Estimate. This calculator provides an approximation based on 2026 federal and Idaho state tax rates. Local taxes, credits, and deductions vary. Consult a tax professional for personalized advice.