All states
Colorado
Flat rateNotes
- Colorado levies a single flat rate of 4.40% (2025) on Colorado taxable income — no brackets, same rate for every filing status and income level. / 科罗拉多州对州应税收入征收 4.40%（2025 年）的单一统一税率——没有累进税档，所有报税身份和收入水平税率相同。
- The tax base is FEDERAL TAXABLE INCOME (Form 1040 line 15), not AGI; Colorado has no standard deduction or brackets of its own. / 计税基数是联邦应税收入（1040 表第 15 行），而非 AGI；科州没有自己的标准扣除额或税档。
- State income tax addback: taxpayers who itemized federally must add back the state income tax they deducted on Schedule A (reduced by any SALT disallowed by the federal $10,000 cap). / 州所得税加回项：在联邦层面分项扣除的纳税人，必须把在 Schedule A 上扣除的州所得税加回（并扣减被联邦 1 万美元 SALT 上限剔除的部分）。
- Federal deductions addback (HB21-1311): for 2025, taxpayers with federal AGI of $300,000+ cap their federal deduction at $12,000 (single/MFS/HoH) or $16,000 (MFJ) and add back the excess, net of the state income tax addback. / 联邦扣除加回项（HB21-1311）：2025 年，联邦 AGI 达到 30 万美元及以上者，将带入科州的联邦扣除额限制为 1.2 万美元（单身/分别申报/户主）或 1.6 万美元（联合申报），超出部分加回（扣除已加回的州所得税部分）。
- DR 0104 subtractions (qualifying pension/Social Security, U.S. government interest, state tax refunds, 529 contributions, etc.) are NOT modelled because the shared input has no fields for them. / DR 0104 的减除项（符合条件的养老金/社保、美国政府利息、州退税、529 计划缴款等）未建模，因为共享输入没有对应字段。