Ovulation Calendar Calculator calculates your personal ovulation calendar to help you achieve pregnancy or to avoid it. The program charts your ovulation cycle on a monthly calendar and an easy to follow graph. You can then use this information predict the calendar days you are most likely to be fertile so that you can achieve or avoid pregnancy. Every woman's ovulation cycle has many days with low probability of pregnancy, and a few good days to get pregnant and best days to conceive a boy or to conceive a girl.