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Spirituality2025-02-08

Havdalah Time Calculator: Why Accuracy Matters for Shabbat

GI

Gal Itach

Founder, ValoremAI

Why Do Shabbat Times Vary by Neighborhood?

In Jewish tradition, time is not a suggestion—it is a law. The exact minute Shabbat ends (Havdalah) varies not just by city, but by your precise elevation and longitude.

The Problem with City Averages

Most "Zmanim" printed in synagogue bulletins are based on a city center calculation.

  • If you live on a hill in Jerusalem, you see the sunset later than someone in the valley.
  • If you live in New York, the difference between Brooklyn and Monsey can be several minutes.
  • A discrepancy of 2-3 minutes can mean inadvertently breaking Shabbat (Chillul Shabbat).

Understanding "Rabenu Tam" vs "The Gra"

There are different Halachic opinions on when nightfall occurs:

  1. The Gra (Vilna Gaon): Calculated based on the sun's position relative to the horizon.
  2. Rabenu Tam: A stricter opinion that requires a longer duration after sunset (often 72 minutes).

The GPS Solution

Shavua Tov uses your device's exact GPS coordinates to calculate Zmanim to the second.

  • Customizable Shitot: Toggle between different halachic opinions instantly.
  • Visual Countdown: Know exactly how many minutes are left until the separation of holy and mundane.
  • Offline Mode: Once coordinates are set, no internet is needed for calculations.

Keep Shabbat with precision. Get Shavua Tov.

Note: The content provided in this article is for informational and educational purposes only. While we aim for high accuracy, details may vary or be simplified. Please handle this information with care and verify specific facts independently.

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