Federal estimated tax payments are designed to ensure that certain individuals pay their fair share of taxes throughout the year. If you don’t have enough federal tax withheld from your paychecks and other payments, you may have to make estimated tax payments. This is the case if you receive interest, dividends, self-employment income, capital gains, a pension or other income that’s not covered by withholding. Individuals must pay 25% of a “required annual payment” by April 15, June 15, September 15, and January 15 of the following year, to avoid an underpayment penalty. If one of those dates falls on a weekend or holiday, the payment is due on the next business day. So the third installment for 2024 is due on Monday, September 16 because the...