What is different in Idaho:
- Flat 5.3% income tax — the highest single rate of any flat-tax state.
- No local income tax anywhere in the state.
- The 5.3% applies to wages after pre-tax deductions like a 401(k).
- Federal income tax, Social Security and Medicare work exactly as in every other state.
What a Idaho paycheck looks like at six salaries
Single filer, paid every two weeks, no 401(k) or other deductions, 2026 figures. Every number below comes from the same tested formulas the calculator above uses.
| Salary | Federal income tax | Social Security + Medicare | Idaho tax | Take-home / year | Take-home / paycheck |
|---|---|---|---|---|---|
| $40,000 | $2,620 | $3,060 | $2,120 | $32,200 | $1,238.46 |
| $58,000 | $4,780 | $4,437 | $3,074 | $45,709 | $1,758.04 |
| $78,000 | $8,330 | $5,967 | $4,134 | $59,569 | $2,291.12 |
| $98,000 | $12,730 | $7,497 | $5,194 | $72,579 | $2,791.50 |
| $128,000 | $19,454 | $9,792 | $6,784 | $91,970 | $3,537.31 |
| $168,000 | $29,054 | $12,852 | $8,904 | $117,190 | $4,507.31 |
Worked example: $72,000, single, paid biweekly
Single filer, paid every two weeks, 4% of salary to a traditional 401(k) — $110.77 per paycheck, $2,880 a year — in Idaho.
- Taxable income: $72,000 − $2,880 401(k) − $16,100 standard deduction (single) = $53,020.00.
- Federal income tax on that amount: $6,376.40 a year.
- Social Security: $4,464.00; Medicare: $1,044.00. The 401(k) does not reduce these.
- Idaho state income tax: $3,663.36.
- Take-home: $72,000 − $2,880 − $6,376.40 − $4,464.00 − $1,044.00 − $3,663.36 = $53,572.24 a year, or $2,060.47 per biweekly paycheck.
Worked example: $21 an hour in Idaho
A single worker earns $21.00 an hour for 36 hours a week: $21.00 × 36 × 52 = $39,312 a year before tax. After federal income tax ($2,537), Social Security ($2,437) and Medicare ($570) ($2,084 of Idaho tax), take-home is $31,684 a year — about $1,218.60 per biweekly paycheck.
Idaho vs Utah: $78,000
The same single worker earning $78,000, paid biweekly with no 401(k). Idaho's 5.3% takes $4,134 a year; Utah's 4.5% takes $3,510.
| Idaho | Utah (4.5% flat) | |
|---|---|---|
| Federal income tax | $8,330 | $8,330 |
| Social Security + Medicare | $5,967 | $5,967 |
| State income tax | $4,134 | $3,510 |
| Take-home per year | $59,569 | $60,193 |
The Idaho worker keeps $624 less per year than the Utah worker — about $24.00 per paycheck. To compare every no-tax and flat-tax state side by side, see take-home pay by state. Also see our Utah paycheck calculator.
What Idaho does not tax — and what it does
Idaho's 5.3% is the highest single-rate income tax in the nation — flat doesn't always mean low. There is no local income tax. Idaho's 6% sales tax does some of the remaining work, with a per-person grocery tax credit softening it for residents at filing time.
What this page leaves out
Child and dependent credits, itemized deductions, health premiums, 401(k) contributions beyond the examples above, bonuses and overtime are not in the simplified calculator — the full paycheck calculator covers all of them, with Idaho at its 5.3% flat rate. For exact figures use your employer's payroll system or the IRS Tax Withholding Estimator.
Sources and review
Brackets and standard deductions come from IRS Revenue Procedure 2025-32. The Social Security wage base comes from the Social Security Administration, and Idaho’s 5.3% flat rate is confirmed by the Tax Foundation's 2026 state rates. Last reviewed September 2026. See our methodology for how every figure is checked.