Zman

Mathias Erligmann

About this app

Zman shows the present moment in Jewish time, and only in Jewish time: the Hebrew date, the hour of the day, the chelek and the rega, with no Gregorian date and no civil clock.

The day begins at 18:00, Jerusalem mean time. It has 24 hours; each hour, 1,080 chalakim; each chelek, 76 rega’im (Rambam, Hilchot Kiddush HaChodesh). These divisions are proportions of the day, not seconds: a day is one real rotation of the Earth, however long it lasts.

That is why Zman does not follow the atomic clock but UT1, the time scale that follows the Earth’s rotation as measured by the IERS. The app counts rega’im on your phone and regularly re-syncs with the zman.technology server, which applies the measured correction. Offline, it carries on with the last known correction.

• The Hebrew date in letters and numbers, the day of the week
• Hour · chelek · rega, live
• The number of rega’im since the epoch, the molad Tohu
• The state of the measurement: age of the IERS data, measured or predicted
• The luach: each Hebrew month as a grid, Sunday to Shabbat, with its festivals, Rosh Chodesh and its molad
• The festivals and fasts of the year, postponements included (fasts moved past Shabbat, Ta’anit Esther brought forward, Yom HaAtzmaut shifted), with a countdown to the next one
• Israel or the diaspora: one or two days of yom tov
• The counting of the omer, day by day
• The molad: a countdown in days, hours, chalakim and rega’im to the next one, and the year’s moladot in the form announced in synagogue
• The structure of the year: length, keviah, place in the nineteen-year cycle, length of each month
• Reminders, scheduled on the device: Rosh Chodesh, festivals and fasts the evening before, the molad at the moment of the molad
• The site’s texts (manifesto, method, API, privacy), readable in the app
• A home screen widget, with the elapsed part of the hour
• A Wear OS app, with a tile and watch face complications: the Hebrew date and the hour of the day on your wrist
• In English, French and Hebrew

The calendar is computed from the rules of the fixed calendar (molad, dehiyot), checked by tests. Method and sources: zman.technology/en/methode.

No account, no ads, no tracking. The API data is published under CC BY 4.0, the code under the MIT licence.

What’s new

New: the luach month by month, festivals and fasts (postponements included, Israel or diaspora), the Omer, the molad with countdown and announcements, the structure of the year, optional reminders, and the manifesto to read in the app.