Kentucky breaks the usual pattern in this batch in a quiet way. The standard deduction is $3,360 for single filers and $3,360 for joint filers as well, not double for a joint return, so a joint household earning $80,000 in total pays the same Kentucky state tax as a single filer on the same salary, on the calculator's basis. Readers who assume a joint return always gets a larger deduction will get this state wrong.
Enter your salary and filing status to see the Kentucky line alongside federal tax and FICA.
Worked example: $80,000, no pre-tax deductions
Take a filer with an $80,000 salary and no pre-tax deductions. State taxable income is $80,000 minus the $3,360 standard deduction, which is $76,640. At the flat 3.5 percent rate, the state tax is $2,682.40. Paid biweekly, that is about $103.17 per paycheck, and the effective rate on gross pay is about 3.35 percent.
Because the deduction is the same for single and joint filers in the table, the joint figure at the same $80,000 total is also $2,682.40. That does not mean joint filing never matters in Kentucky, it means it does not matter through this deduction on a single $80,000 total. A joint household with two incomes, or with different pre-tax deductions, will still have a different total, but not because the standard deduction doubled.
Do not assume the joint deduction is double. The Tax Foundation table shows $3,360 for both single and joint, and this guide follows that table rather than correcting it by assumption.
What the flat figure leaves out
Local taxes are excluded from the Kentucky figure. As with any flat rate, a raise is priced at the same rate: every extra dollar of taxable income adds 3.5 cents of Kentucky tax, at $80,000 or at higher incomes, with no bracket threshold to cross. The gap between the marginal rate of 3.5 percent and the effective rate on gross pay of 3.35 percent is entirely the $3,360 deduction, which shields a small slice of the salary.
Source for the rate and deduction: Tax Foundation 2026 State Income Tax Rates and Brackets. This is general information about Kentucky's flat schedule, not a determination for an individual return. The federal brackets guide linked from the paycheck hub covers the federal slice on the same salary.
FAQs
Is Kentucky's joint deduction really the same as single?
Yes, in the Tax Foundation table used here: $3,360 for both. Do not double it by assumption; check the table if a future year changes it.
Does filing jointly lower Kentucky tax at $80,000?
Not through the standard deduction, on the calculator's basis. Single and joint filers both pay $2,682.40 on the same $80,000 total in this example.
Does a raise change the Kentucky rate?
No, the rate stays 3.5 percent. Every extra dollar of taxable income adds 3.5 cents of Kentucky tax, with no threshold to cross.