I haven’t studied every online tool for period tracking but this one appears to be the most sophisticated yet: MikvahCalendar.com helps observant Jewish women track their cycles, including her niddah (ritually impure) time. It automatically calculates sunrise and sunset, sends email or text reminders, and can be customized for Chabad, Ashkenazic, and Sephardic traditions. And it’s Rabbincally Approved.
Menstrual Tracking 2.0March 22nd, 2010 by Elizabeth Kissling
Readers should note that statements published in Menstruation Matters are those of individual authors and do not necessarily reflect the positions of the Society as a whole.