Louisiana taxes federal AGI at a flat 3% after its own standard deduction — $12,875 single, $25,750 joint, and $25,750 for heads of household too, which is unusually generous. There is no personal exemption. Neither federal deduction reduces Louisiana tax.
What it means on a real paycheck
Take a single filer earning $50,000 a year, $8,000 of it in tips. Against the same person with no tips to declare, the federal deduction is worth $960.
In Louisiana it is worth nothing extra. The state bill is identical either way, so $960 is the whole of it.
How Louisiana works out the tax
Louisiana charges a flat 3%, after a standard deduction of $12,875 single or $25,750 filing jointly. It begins from your federal adjusted gross income and applies its own reliefs from there.