All states
Idaho
Flat rateNotes
- Idaho levies a single flat 5.3% individual income tax rate for 2025; House Bill 40 (signed March 6, 2025) cut the rate from 5.695% to 5.3% effective for the 2025 tax year. / 爱达荷州 2025 年个人所得税为 5.3% 的单一统一税率；第 40 号众议院法案（2025 年 3 月 6 日签署）将税率从 5.695% 下调至 5.3%，自 2025 纳税年度起适用。
- Idaho applies a 0% zero-rate bracket before the flat rate: the first $4,811 of Idaho taxable income (single / married filing separately) or $9,622 (married filing jointly / head of household) is taxed at 0%. / 爱达荷州在统一税率之前设有 0% 的零税率档：州应税收入的前 4,811 美元（单身/夫妻分别申报）或 9,622 美元（夫妻联合申报/户主）按 0% 征税。
- Idaho's standard deduction equals the federal standard deduction for the year, so it tracks the federal amount automatically; Idaho Form 40 starts from federal taxable income. / 爱达荷州的标准扣除额与当年联邦标准扣除额相同，会自动随联邦金额变动；爱达荷州 Form 40 以联邦应税收入为起点。
- Not modelled: Idaho-specific additions and subtractions (e.g. the state-income-tax addback on itemized deductions, retirement-benefit and capital-gains deductions) on Form 39R, which the shared input cannot capture. / 未建模：Form 39R 上爱达荷州特有的加项与减项（如分项扣除中的州所得税加回、退休福利与资本利得扣除），因为共享输入无法表达这些字段。