A reliable period and ovulation calculator app, even when you have irregular periods. Can’t remember the date of your last period? Want to know when your next period is coming? Period Tracker - Ovulation & Pregnancy Calendar is a simple & elegant way to view past and predict future periods, fertile days and ovulation days. Accurate & Reliable ★ Accurate predictions based on your own menstrual history. ★ Becomes even more accurate with usage, by way of machine learning (AI). Beautiful Design ★