Fertility Calendar tracks and predicts your period, ovulation and fertile window, shows your Pregnancy Chance every day and everything about woman who try to conceive, pregnant or birth control. It tracks your periods, cycles, ovulation and the chance of conception. Period Calendar is used to recording and predicting the period, fertile and ovulation days. Due to individual differences, such as age, period cycle, period regularity, etc., Period Calendar may not always predict accurately. Therefore, it can be used to track your personal information, rather than as the only standard to prevent unwanted pregnancy. Natural birth control may cause unwanted pregnancy, please use safe and effective way to protect the intercourse.