Idaho Income Tax Calculator (2025 Flat Rate)

The formulas

• Taxable income = income - standard deduction - personal exemptions (when applied), not below zero
• Tax = 5.3% x Idaho taxable income above $4,811 ($9,622 joint, head of household or surviving spouse) for 2025
• Standard deduction equals the federal amount: $15,750 single or separate, $23,625 head of household, $31,500 joint (2025)
• Idaho income tax = tax from the rate schedule

How it works

Tax year: 2025. These are the latest full return figures Idaho has published.

Idaho taxes income at a flat 5.3%. Enter income before state deductions and choose whether to apply the state standard deduction and personal exemptions, or enter taxable income and switch them off. The tool computes state income tax only; credits other than those named are not applied.

HB 40 (2025) cut Idaho's rate to 5.3 percent, retroactive to January 1, 2025, and the rate is unchanged for 2026. Income up to the zero bracket is untaxed: $4,811 single or separate and $9,622 joint, head of household or surviving spouse for 2025. The Tax Commission indexes that amount each year and had not published the 2026 figure when this page was checked, so the tool uses 2025.

Idaho starts from federal AGI and allows the federal standard deduction, which HB 559 (2026) conformed to the 2025 federal amounts. Idaho has no personal exemption. The grocery credit and other credits are not applied.

Local taxes: Idaho cities and counties do not levy a local income tax.

Illustrative figures only. Check the result against your firm's methodology before relying on it.

Common questions

Sources

• Idaho Code 63-3024 (rate, zero bracket, joint and head of household treatment)
• Idaho State Tax Commission, 2025 Form 40/43 instructions (EIN00046, zero bracket $4,811 / $9,622, 5.3%, standard deduction)

Runs in your browser. The figures you type are not sent to CORAA or stored. Check the result against your firm's methodology before relying on it.