Kentucky charges a flat 3.5% on federal AGI less a $3,360 standard deduction. Under HB 757 it decoupled from both federal deductions, so neither reduces your Kentucky tax. Many Kentucky cities and counties also levy a local occupational tax, which is not included here.
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 Kentucky it is worth nothing extra. The state bill is identical either way, so $960 is the whole of it.
How Kentucky works out the tax
Kentucky charges a flat 3.5%, after a standard deduction of $3,360. It begins from your federal adjusted gross income and applies its own reliefs from there.