◆ About ZmanimPro

Last updated: August 2026

ZmanimPro is a bilingual (English & Hebrew) Jewish calendar that provides precise Shabbat times, Zmanim, Hebrew–Gregorian date conversion, and Torah portion readings for any location worldwide.

Our Approach: Transparency Over Personality

ZmanimPro is operated as an editorial project, not by a single named author. Rather than inventing a rabbinic persona or attributing articles to an individual, we cite primary sources directly. Every calculation method, halachic ruling, and custom referenced on this site is traceable to one of the sources listed below.

Halachic Sources

• Shulchan Aruch, Orach Chayim — the foundational code of Jewish law, sections 261–297 cover the laws of Shabbat.
• Mishna Berura by Rabbi Yisrael Meir Kagan (the Chofetz Chayim) — the standard 20th-century commentary on the Shulchan Aruch.
• Talmud Bavli, Masechet Shabbat — the primary Talmudic source for Shabbat laws.
• Sefer HaYereim by Rabbeinu Elchanan — source of the Jerusalem 40-minute candle-lighting custom.
• Magen Avraham and GRA (Vilna Gaon) — the two primary opinions on how to compute halachic hours; we provide both.
• Rambam (Maimonides), Hilchot Kiddush HaChodesh — the algorithmic basis of the Hebrew calendar, as codified in the 12th century.

Scientific & Computational Sources

• NOAA Solar Calculator — based on Jean Meeus, Astronomical Algorithms, 2nd edition (1998). The sun's position is accurate to ±0.01°, corresponding to roughly ±1 minute of time at most latitudes.
• KosherJava Zmanim API by Eliyahu Hershfeld — the industry-standard open-source library for halachic time calculations, maintained since 2004. We use its PHP port, PhpZmanim (LGPL-2.1), as our core calculation engine.
• Sefaria — open-source digital library of Jewish texts (Tanach, Talmud, Halacha); used for source verification. sefaria.org
• U.S. Naval Observatory — authoritative astronomical data for solar position calculations. aa.usno.navy.mil
• GeoNames — geographic coordinates for cities worldwide.

Editorial Policy

1. No invented content. Every halachic opinion, custom, and source on this site is real and verifiable.
2. Algorithmic transparency. Our calculation methods are documented in full on the Algorithm page.
3. Bilingual by design. The Hebrew version (עברית) is not a machine translation; it is written for Hebrew speakers, especially in Israel.
4. Open-source foundation. Our core engine is the LGPL-2.1 PhpZmanim library, which anyone can inspect and verify.
5. No paid endorsements. We do not accept payment for content placement.

Limitations & Disclaimer

Zmanim calculations are highly accurate but depend on your exact location and elevation. For final halachic rulings — especially for stringencies (chumrot) or in cases of doubt — consult a qualified rabbi. The times published here are intended as a reference tool and should not replace local communal practice.

Contact

Found an error or have a suggestion? Email [email protected].