Idaho income tax goes up to 5.3% at the top bracket. Calculate your combined federal + state effective tax rate for 2026. Formula shown, sources cited — no account required.
The state applies a flat income tax rate of 5.3% to all taxable income, regardless of how much you earn. This simplicity is helpful for planning — there are no bracket thresholds to track, and your marginal rate equals your effective rate. For the median earner at $81,166, state income tax represents roughly $4,302 annually before federal standard deductions or itemized deductions reduce taxable income. Federal taxes layer on top with their own graduated brackets, so the combined marginal rate for a middle-income household typically lands in the mid-twenties percent range. One notable state feature is a grocery tax credit, which provides a modest refundable credit to lower-income households to offset the sales tax on food. There is no deduction for contributions to retirement accounts beyond what federal rules allow, but the flat rate means any additional earnings are taxed at the same 5.3% regardless of income level. If you are comparing a job offer here against opportunities in states with no income tax, the tax bracket calculator can show you the exact annual difference in after-tax pay.
Idaho Tax Brackets Explained (2026)
Idaho has a state income tax with a top marginal rate of 5.3%. On top of federal rates (10%–37%), residents can face a combined marginal rate exceeding 35% at higher income levels. However, your effective rate is always lower than the marginal rate because only income above each threshold is taxed at that bracket's rate.
The median household in Idaho earns $81,166/year. At that income (single filer), the federal effective rate is approximately 12–14%, bringing total income tax (federal + state) to roughly 15–18%.
How Marginal vs. Effective Rate Works
The marginal rate is the rate on your last dollar of income — it does not apply to all income. The effective rate is your total tax divided by total income. For example, someone earning $100,000 in Idaho has a 22% federal marginal rate but an effective federal rate of roughly 15%, because the first $44,725 (2024) is taxed at 10% and 12%, not 22%.