Use our free online fertility calculator to determine your peak fertility dates for the coming year. This can be especially helpful for couples who need to time for "baby-making sex".

This calculator is based on the fact that

1. ovulation occurs 14 days before the next menstrual period is due; and that
   
   
2. fertility peaks on the day of ovulation, and for 4 days prior to this.

Just enter :

1. The first day of your last menstrual period ( the day the bleeding starts)
   
   
2. The length of your menstrual cycle ( number of days from the first day of your period to the first day of the next period)

First Day of Last Period Cycle Days Choose No of Days 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

Interested in learning more ? You can find out more about how your body works and how you can use the signals it gives you by tracking your ovulation .