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. Find the Moon Hold your phone up to the sky and it points to the moon — the direction, the height, and how long before it sets. For Kiddush Levana, when knowing the zman is not the hard part. 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.