Do these upcoming tax deadlines apply to you?

You might think tax filing time is over for 2013, but that's not necessarily the case for many taxpayers. There are several important tax deadlines in September and October. Check the list below to see if any of them apply to you or your business.

September 16 - Due date for third quarter installment of 2013 individual estimated income tax.

September 16 - Filing deadline for 2012 tax returns for calendar-year corporations that received an extension of the March filing deadline.

September 16 - Filing deadline for 2012 partnership tax returns that received an extension of the April filing deadline.

September 16 - Due date for third quarter installment of 2013 corporate estimated tax.

October 1 - Deadline for self-employed individuals and small businesses to establish a SIMPLE retirement plan for 2013.

October 15 - Filing deadline for 2012 individual income tax returns that received an extension of the April filing deadline.

October 15 - Deadline for undoing a 2012 conversion of a regular IRA to a Roth IRA and switching the Roth back to a regular IRA without penalty.