State Tax · ID · 2025
Idaho Income Tax Calculator
Idaho uses a flat 5.7% income tax rate for 2025. Enter your income and filing status to compute your state tax liability.
Your information
Wages, salary, or other ordinary income
Informational only — not professional tax advice.
Enter your income to see your Idaho state income tax breakdown — bracket by bracket with marginal and effective rates.
Methodology
How Idaho income tax is calculated
Idaho applies a single flat rate of 5.7% to all taxable income. The standard deduction for Idaho single filers is $15,000. Taxable income equals gross income minus your deduction (standard or itemized).
Formula
Taxable income = Gross income − Deduction Idaho tax = Taxable income × 5.7%
Tax year scope
This calculator uses 2025 tax year rates as published by the Idaho State Tax Commission.
Marginal vs. effective rate
Because Idaho uses a flat rate, your marginal and effective state income tax rates are the same percentage (5.7%). Your effective rate as a share of gross income will be lower because the deduction reduces taxable income before the rate is applied.
Limitations
- Covers state income tax only — federal income tax is separate.
- Does not account for tax credits, phase-outs, or alternative minimum tax provisions.
- Local income taxes (where applicable) are not modeled.
Last reviewed: January 2025. Rates reviewed annually after Idaho State Tax Commission publishes updated tables.
Frequently asked questions
What is the Idaho income tax rate for 2025?
Idaho uses a flat income tax rate of 5.7% on all taxable income in 2025. A flat rate means everyone pays the same percentage of their taxable income regardless of how much they earn.
What is the difference between marginal and effective tax rate?
For flat-rate states like Idaho, your marginal rate and effective rate are the same percentage — both equal the flat rate (5.7%). However, the effective rate as a share of your gross income will be lower than 5.7% because your deduction reduces taxable income before the rate is applied.
Does this calculator include federal income taxes?
No — this calculator covers Idaho state income tax only. You still owe federal income tax separately. Use the CiteTax Federal Income Tax Calculator to compute your federal liability.
When is the Idaho state income tax return due?
Idaho state individual income tax returns are generally due April 15 of the following year, matching the federal deadline. Extensions may be available. Verify the current deadline at the Idaho State Tax Commission.
Related tools
Enter your income and filing status to see exactly how the 2025 U.S. tax brackets apply — marginal rate, effective rate, and every dollar of tax shown bracket by bracket.
Open tool →Tax Bracket ExplorerSee all seven 2025 federal tax brackets in one table — where each bracket starts, ends, how wide it is, and the total tax owed at each ceiling.
Open tool →Marginal vs. Effective Tax Rate ExplainerMost people misunderstand how tax brackets work. This tool shows exactly how a raise, bonus, or extra income is taxed — and why your marginal rate isn't what you actually pay.
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