Kentucky Quarterly Tax Calculator 2026

If you are self-employed, a freelancer, or have significant income not subject to withholding in Kentucky, you are likely required to make quarterly estimated tax payments. The federal quarterly due dates are April 15, June 15, September 15, and January 15 (of the following year).

In addition to federal quarterly payments, Kentucky requires its own estimated tax payments if you expect to owe state income tax. Kentucky has a flat 4.0% income tax rate, and state estimated payments typically follow a similar quarterly schedule. Check with the Kentucky Department of Revenue for specific state estimated payment forms and due dates.

Kentucky offers a standard deduction of $3,160 for single filers and $6,320 for married filing jointly. This deduction reduces your state taxable income when calculating your estimated quarterly payments.

To avoid underpayment penalties, aim to pay at least 90% of your current year tax liability or 100% of your prior year tax liability (110% if your AGI exceeded $150,000). The calculator above compares both methods and recommends the lower amount.

Remember that quarterly payments are cumulative. If you underpay one quarter, you can increase payments in subsequent quarters. However, you may still incur a small penalty for the quarter you underpaid.