State income tax
Idaho state income tax: 5.695% flat rate
Idaho taxes wages at a flat 5.695% \u2014 the same rate on every dollar of taxable income.
Reviewed by BoringToolsKit · August 26, 2026 · Simplified illustration for a single filer \u2014 excludes the standard deduction, exemptions, credits, and any local/city income taxes, and real state rules differ (married-filer brackets, phase-outs, inflation indexing). Rules change year to year; verify with the state revenue department. Informational, not tax advice.
How Idaho taxes income
A flat-rate state taxes every dollar of taxable income at the same percentage, so the marginal rate equals the effective rate before deductions. Idaho\u2019s flat rate is 5.695%.
Run your numbers
$80,000 single filer in Idaho
Graduated brackets tax only the income inside each band. On $80,000, Idaho taxes each slice like this:
| Rate | Starts at | Taxed amount | Tax |
|---|---|---|---|
| 5.695% | $4,673 | $75,327 | $4,290 |
| Total | $4,290 |
Marginal rate 5.7% \u00b7 effective rate 5.36% \u2014 the last dollar is taxed at the marginal rate, but the whole income averages to the effective rate.
| Rate | Single-filer taxable income |
|---|---|
| 5.695% | Over $4,673 |
Single-filer tax at common incomes
Estimated state income tax before deductions and credits:
| Income | Tax | Effective rate |
|---|---|---|
| $50,000 | $2,581 | 5.16% |
| $100,000 | $5,429 | 5.43% |
| $150,000 | $8,276 | 5.52% |
Simplified illustration for a single filer \u2014 excludes the standard deduction, exemptions, credits, and any local/city income taxes, and real state rules differ (married-filer brackets, phase-outs, inflation indexing). Rules change year to year; verify with the state revenue department. Informational, not tax advice.
State income tax questions, answered
What is the difference between marginal and effective state income tax?
Your marginal rate taxes only the last dollar of income; your effective rate is total state tax divided by total income. In a graduated state most filers\u2019 effective rate is well below the top marginal rate.
Does Idaho tax all income at the top rate?
No. Graduated brackets tax only the income inside each band, so the rate you see on the last dollar is not the rate on the first dollar.
Which states have no individual income tax?
Alaska, Florida, Nevada, New Hampshire, South Dakota, Tennessee, Texas, Washington, and Wyoming collect no state individual income tax on wages.
Is this calculator tax advice?
No \u2014 this is a simplified illustration for a single filer that excludes the standard deduction, exemptions, credits, and local/city taxes. Verify with the state revenue department.
Put the rate to work
See the state income tax comparison table, the full bracket index, or the salary-to-hourly converter.