K-210 Underpayment of Individual Estimated Tax Rev. 7-22. If you are an individual taxpayer (including farmer or fisher), use this schedule to determine if your income tax was fully paid throughout the year by withholding and/or estimated tax payment 2026

1. Click ‘Get Form’ to open it in the editor.
2. Enter your name and Social Security number at the top of the form.
3. Complete lines 1 through 4 using information from your income tax return for both the current and prior year.
4. In Part I, calculate your cumulative withholding and timely paid estimated tax payments for each quarter, entering totals on lines 5 and 6.
5. Determine if you qualify for exceptions by comparing line 7 with lines 8 and 9a or 9b. If line 7 meets or exceeds these amounts, no penalty is due.
6. For Part II, calculate the amount of underpayment on line 10 by selecting the lesser value from the applicable computations.
7. Follow through with calculating penalties based on the number of days late as indicated in lines 12 and 13, applying appropriate rates on lines 14 and 15.
8. Finally, sum up any penalties on line 17 and ensure this amount is also recorded on Form K-40.

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