Kentucky State Income Tax Withholding

Reference Number: NFC-24-1709674769
Published: March 7, 2024
Effective: Pay Period 02, 2024


The income tax withholding formula for the State of Kentucky, includes the following changes:

No action on the part of the employee or the personnel office is necessary.

Tax Formula

State Abbreviation: KY
State Tax Withholding State Code: 21
Acceptable Exemption Form: K-4
Basis for Withholding: N/A or Flat Rate
Acceptable Exemption Data: None
TSP Deferred: Yes
Special Coding: None
Additional Information: None

Withholding Formula (Effective Pay Period 02, 2024)

  1. Subtract the nontaxable biweekly Thrift Savings Plan contribution from the gross biweekly wages.
  2. Subtract the nontaxable biweekly Federal Health Benefits Plan payment(s) (includes dental and vision insurance program and flexible spending account-health care and dependent care deductions) from the amount computed in step 1.
  3. Add the taxable biweekly fringe benefits (e.g., taxable life insurance) to the amount computed in step 2 to obtain the adjusted gross biweekly wages.
  4. Multiply the adjusted gross biweekly wages by the number of pay dates in the tax year to obtain the gross annual wages.
  5. Subtract the standard deduction of $3,160 from the result of step 4 to compute the taxable income.
  6. Apply the flat tax rate of 4.0 percent to the annual taxable wages in step 5 to determine the annual tax amount.
  7. Divide the annual Kentucky tax withholding calculated in step 6 by the number of pay dates in the tax year to obtain the biweekly Kentucky tax withholding.


To view the updated tax formula, go to the HR and Payroll Clients page from the MyNFC drop-down menu on the National Finance Center (NFC) Home page. Select the Publications tab and select Taxes from the Publications menu to launch the tax map. Select the desired State from the map provided for the formula.

Previous Tax Bulletin


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