Nishmat's Women’s Health and HalachaIn memory of Chaya Mirel bat R' Avraham

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Online veset calendars

16 November, 2015


How does a Chabad mikvah calendar differ from the Ashkenazi calendar? I am Ashkenazi and I was wondering about using, but I understand it calculates only based on the Chabad calendar. Can you advise how this would differ and whether it would be possible to use their calendar? Thank you.


Chabad veset calculations do differ significantly from non-Chabad custom: the interval is calculated from the hefsek taharah and not from the onset of flow and the interval is counted by onot (days or nights), not by full Hebrew calendar days.

We would not suggest using a Chabad online calendar, unless there are non-Chabad settings available.  (There do not seem to be on the site you mentioned.)  There are other online veset calendars available for non-Chabad custom.  Please see our posted question on the topic for a list. Note that we have not personally reviewed any of these applications.

Even if you are using an online veset calendar, you should know the basics of keeping a calendar by hand. If you'd like to review how to keep a traditional calendar, please see our site's article, "How to Keep a Calendar."

Please write back with any further questions.

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