Idaho's 5.8% Flat Income Tax
Idaho applies a flat 5.8% tax on all taxable income. Unlike progressive systems where higher income pushes you into higher brackets, every dollar in Idaho is taxed at the same rate. This simplifies calculations and means your marginal and effective state tax rates are identical (or nearly so). On $85,000, state tax is $4,930/year. On $200,000, it's $11,600/year. The proportionality is straightforward.
Maximizing Your Take-Home Pay in Idaho
The most effective lever for increasing take-home pay in Idaho is pre-tax retirement contributions. A traditional 401(k) contribution reduces your taxable income for both federal and state taxes. At $85,000 in Idaho, your combined marginal rate (federal + state) is approximately 28%. Every $100 directed to a pre-tax 401(k) saves $28 in taxes — you sacrifice $72 in take-home pay, not $100. HSA contributions (if you have a high-deductible health plan) go further — they reduce federal, state, AND FICA taxes, saving roughly 36% on every contributed dollar.