You must file or mail your final return on or before April 15. The postmark determines date of mailing.
Estimate due dates are:
- Quarter 1: April 15
- Quarter 2: July 15
- Quarter 3: October 15
- Quarter 4: January 15
- Additional Payments: April 15* of the following year
*Tax Day deadline is April 15 unless the date falls on a weekend or holiday, then it is the next business day.