Online calculators are available at:
- www.mikvahcalendar.com (Ashkenazic, Sephardic, and Chabad customs)
- http://www.mymikvahcalendar.org, or www.mymikvahcalendar.org/mobile for smartphones (Chabad customs only)
This is not an endorsement of any product. Please note that we have not tested these applications, and cannot vouch for their accuracy. Even with such programs, it is important for women to understand how to calculate anticipated menses, to ensure that the application is correct. We are always available to help individual women work out their calendars and review how to keep them, whether via this site, our hotline, or referrals to yoatzot and rabbis.
This answer is updated as of March, 2019.