Individual Estimated Payment

If you wish you may schedule estimated payments for up to an entire year in
advance. For most taxpayers, payments are due on the following dates.

If the 15th is on a weekend or holiday, 
the payment is due on the next business day.

4/15 (first quarter and income tax)
6/15 (second)
9/15 (third)
1/15/of-next-year (fourth)