Chabad.org Labs

Calendar tools

Experiments in the Jewish calendar — each one a small, single-purpose page. Prototypes: check anything consequential with your rav.

Molad Calculator The moment of the new moon for any Hebrew month — the traditional announcement in hours and chalakim, with an animated explanation of how it is calculated. Kiddush Levana The window for blessing the moon: earliest and latest, the three opinions on the deadline, and whether it falls on Motzei Shabbos. The Seventh Hour When not to make Kiddush on Friday night — the seventh hour after chatzos, for your location and date. Bulk Hebrew Date Converter A list of dates in, a list of Hebrew dates out — either direction. Includes a JSON API documented for AI agents.