Ovulation Calendar - Fertility Calculator

Free Online Ovulation Calendar

The BabyHopes free ovulation calendar will help you calculate when you are most fertile during your menstrual cycle. For most women, ovulation occurs approximately 14 days before the start of your next menstrual period. Knowing when you ovulate will help you have sex at a time that will increase your chances of getting pregnant.

Calculating Your Cycle Length

To figure out when you ovulate, you need to know how long your menstrual cycle is. This is not the number of days you bleed while on your period.

Your cycle length is calculated by counting the number of days from the first day of menstruation to the day before the following menstrual period starts.

If you don't want to count how long your cycle is on a calendar, you can just click here and enter the dates and we will automatically calculate your cycle length for you.

Calendar Limitations

  • Cycle lengths of more than 35 days are too long for appropriate calculations.

  • Cycle lengths of less than 21 days are too short for appropriate calculations.

  • If your menstrual cycle is too short or long, of if you have very irregular cycles, you may want to consider trying a natural fertility supplement to help balance your hormones and encourage regular ovulation.

  • Our calendar cannot be used to reliably prevent pregnancy.

Calculate When You Are Most Fertile

First day of last menstrual period:
Length of cycle: days
Show me my most fertile days for: Months
Show me the best days to have sex in order to increase my chances of having a baby girl or baby boy.

Scroll down to see your most fertile days!


  • Helps you figure out the 4 most fertile days of your cycle.

  • Calculate your most fertile days for up to 3 months in the future.

  • Our ovulation calendar helps you figure out when the best time to take a pregnancy test and get a positive result if you are pregnant.

  • The BabyHopes ovulation calendar lets you calculate the best times to have sex, based on if you want to have a boy or a girl baby. The suggestions are based on Dr. Landrum Shettles book, "How to Choose the Sex of Your Baby"