You can go on babycenter.com and check the ovulation calendar. Type in the first day of your last period and it will tell you the days you are fertile and the due dates. This is for May 16:
Fertile June 24, 2011 - June 29, 2011
Due Date March 19, 2012
fertile July 22, 2011 - July 27, 2011
due April 16, 2012
fertile August 19, 2011 - August 24, 2011
due May 14, 2012
September 16, 2011 - September 21, 2011
June 11, 2012
October 14, 2011 - October 19, 2011
July 9, 2012
November 11, 2011 - November 16, 2011
August 6, 2012