Idaho Capital Gains Tax Calculator
Idaho taxes capital gains as ordinary income at the state level, which means a gain on selling shares, property or other investments is added to your other income and taxed using the Idaho income tax brackets, with no separate preferential long-term rate like the federal system provides. This calculator estimates the Idaho state tax on a capital gain by stacking the gain on top of your other taxable income and applying the sourced Idaho State Tax Commission brackets for tax year 2025, then taking the difference. Enter your gain, your other annual taxable income and your filing status to see the state tax attributable to the gain and the effective rate on it. The result is the Idaho state portion only; federal capital gains tax, which has separate short-term and long-term rates set by the IRS, is calculated separately. Because the gain stacks on your other income, the same gain is taxed at a higher rate the more you already earn. Some states provide specific exclusions or preferential treatment for certain gains; this tool uses the standard ordinary-income method and links the Idaho State Tax Commission so you can confirm any special rule that applies to you.
Idaho taxes capital gains as ordinary income. A $20,000.00 gain on top of $60,000.00 of other income (single) adds about $1,139.00 in Idaho state tax, an effective rate on the gain of 5.70%.
How Idaho taxes capital gains
Idaho taxes capital gains as ordinary income, so the gain is added to your other income and taxed at the Idaho bracket rates.
state tax on gain = state income tax on (other income + gain) - state income tax on (other income)
effective rate on gain = state tax on gain / gain x 100
Idaho capital gains tax: frequently asked questions
How are capital gains taxed in Idaho?
Idaho taxes capital gains as ordinary income at the state level: the gain is added to your other taxable income and taxed using the Idaho income tax brackets published by the Idaho State Tax Commission. This calculator applies those brackets to your gain. Some states provide specific exclusions or rates for particular gains; confirm your situation with the Idaho State Tax Commission.
How much state tax will I pay on a $20,000.00 capital gain in Idaho?
Stacked on $60,000.00 of other income, a $20,000.00 gain adds about $1,139.00 of Idaho state income tax for a single filer, an effective rate on the gain of 5.70%. Your figure depends on your total income and filing status; enter them above.
Does Idaho have a separate long-term capital gains rate?
Most states, including the default treatment here, tax long-term and short-term capital gains at the same ordinary income rates, unlike the federal system which has preferential long-term rates. Any state-specific exclusion or preferential rate is set by the Idaho State Tax Commission; this calculator uses the ordinary income method and links the source.
What is Idaho's state income tax rate for 2025?
Idaho's flat income tax rate is 5.695% for tax year 2025. The rate was established by Idaho HB 1 (2022 special legislative session) and applies to all Idaho taxable income for all filing statuses, per Idaho Code §63-3024.
What standard deduction can Idaho residents use?
Idaho conforms to the federal standard deduction. For 2024, the amounts are $14,600 for single filers and married filing separately, $29,200 for married filing jointly, and $21,900 for head of household. These figures are adjusted annually for inflation by the IRS, and Idaho adopts the updated federal amounts each year.
When did Idaho change to a flat income tax?
Idaho adopted its current flat rate of 5.695% through HB 1, passed during a 2022 special legislative session. The flat rate replaced a graduated structure and became effective for tax year 2023. The change was intended to simplify the state tax code and reduce the overall income tax burden.
Does Idaho conform to federal tax rules?
Yes. Idaho conforms to many federal income tax rules, including the federal standard deduction, federal adjusted gross income as the starting point for Idaho taxable income, and certain federal deductions and credits. Idaho does make some modifications to federal AGI on the state return. Review the Idaho State Tax Commission guidance at tax.idaho.gov for the current list of additions and subtractions.
Official sources
- Idaho income tax rates applied to capital gains (tax year 2025): Idaho State Tax Commission, as at Jun 12, 2026.
Reviewed by the CalculatorHub team, edited by James Graham, 25 June 2026. See our methodology. General information, not financial or tax advice. State-specific exclusions, if any, are set by the Idaho State Tax Commission.