All states
Louisiana
Flat rateNotes
- Louisiana switched to a single flat 3% individual income tax rate for 2025; Act 11 of the 2024 Third Extraordinary Session repealed the old graduated schedule (1.85% / 3.5% / 4.25% for 2022–2024). / 路易斯安那州 2025 年改为 3% 的单一统一税率；2024 年第三次特别会议第 11 号法案废除了原有的累进税率表（2022–2024 年为 1.85%/3.5%/4.25%）。
- The 2025 standard deduction was nearly tripled to $12,500 (single / married filing separately) and $25,000 (married filing jointly / head of household / qualifying surviving spouse); these amounts are CPI-indexed starting January 1, 2026. / 2025 年标准扣除额几乎翻三倍，单身/夫妻分别申报为 12,500 美元，夫妻联合申报/户主/合格尚存配偶为 25,000 美元；自 2026 年 1 月 1 日起按 CPI 指数化。
- The deduction for federal income taxes paid is REPEALED for individuals (removed since 2022 by constitutional Amendment 2, and still gone under the 2025 reform); the 2025 IT-540 goes Federal AGI → standard deduction → taxable income with no federal-tax deduction step. / 个人可抵扣已缴联邦所得税的条款已被废除（2022 年起通过宪法第 2 号修正案取消，2025 年改革后依然取消）；2025 年 IT-540 的计算路径为联邦 AGI→标准扣除→应税收入，没有联邦税抵扣环节。
- Act 11 also repealed the per-dependent, over-65, and blind personal exemptions, so — unlike Illinois — there is no per-person exemption to subtract. / 第 11 号法案还废除了按受抚养人、65 岁以上及盲人的个人豁免，因此与伊利诺伊州不同，没有按人头的豁免可供扣减。
- Louisiana starts from federal AGI and conforms to the federal pre-tax 401(k) / HSA treatment, so there are no add-backs. / 路易斯安那州以联邦 AGI 为起点，并遵循联邦的税前 401(k)/HSA 处理，因此没有加回项。
- Not modelled: the narrowed 'excess federal itemized deductions' (IT-540 Lines 9A–9D, now keyed to federal Schedule A medical/dental expenses exceeding the federal standard deduction) and the $12,000 retirement-income exemption for filers aged 65+, since the shared input cannot capture federal Schedule A detail or taxpayer age. This module applies the standard deduction only. / 未建模：收窄后的「超额联邦分项扣除」（IT-540 第 9A–9D 行，现以联邦 Schedule A 医疗/牙科支出超过联邦标准扣除的部分为基准）以及 65 岁以上申报人的 12,000 美元退休收入豁免，因为共享输入无法表达联邦 Schedule A 明细或纳税人年龄。本模块仅适用标准扣除。