Draft This map is decision support, not a psak. Review with a rav before relying on it. Please send feedback with any issues or ways we can make this better. It would be very helpful and greatly appreciated.
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Techum Shabbos

תחום שבת boundary calculator

About
Start with a place

Where will you be for Shabbos?

Enter the address where your techum begins. We’ll guide you through the rest.

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1 Get map data 2 Build the city 3 Draw the techum
See how this calculation worksShow the house chains, 70⅔-amah joins, derived city, squaring, and final 2,000-amah boundary.
2
Confirm the pinYou can drag it to the exact building.
Review & settingsOptional
Halachic profile Defaults & shitos

City status: the sourced rule is 3 courtyards × 2 houses (or the sourced resident-count basis). Six mapped footprints are only a provisional fallback; record the factual basis in the calculation review.

Buildings & data Sources & overrides The calculator automatically uses the configured immutable Overture release and shared reviewed corrections. Refresh bypasses both caches.
Snapshots freeze the fetched data + settings + overrides for a deterministic, reproducible replay (map releases change over time; halachos don't).
Map display Layers & comparison
Reading the audit view
  1. Solid shape: the exact mapped building footprint.
  2. Dotted shape: 70⅔ amos from its walls. Touching a house joins the chain.
  3. Dashed box: a derived settlement after chain and city-merge rules.
  4. Bright box: your selected city’s ribua; the techum is measured from it.

Missing buildings Manual map corrections

Usually nothing is required. If a roof is missing, use the two-click rectangle or trace its corners. It applies immediately and is submitted to the shared review database.

Reviewed city library Published rav-reviewed snapshots

Published entries preserve the reviewer, date, conditions, and source notes. Loading one replaces the current calculation after confirmation.

Validated enclosure Rav-supplied perimeter only

Draw or import a rav-validated hukaf-l'dira wall/eruv perimeter. A yard is not assumed to count merely because it appears fenced in imagery. It remains inactive until you explicitly enable it.

Validated residential yard / subsidiary perimeter: this participates in the 70⅔- and 141⅓-amah wall-to-wall geometry but never counts as another house. Use only after a rav confirms the connection to a dwelling and hukaf l'dirah facts.

What you’re looking at
Pink: your 2,000-amah techum boundary.
Green: the halachic city rectangle used as the starting point—not the town border.
Pale green dashed: the extra karpef before measuring 2,000 amos.
Amber dashed: a second scenario using only clearly tagged dwellings; it can be larger or smaller.
Green buildings: identified dwelling Orange: use unknown
Purple: needs review Gray: excluded non-dwelling
Click a building to include or exclude it manually. Hover a boundary for its name.
Built for careful review · Method & halachic sources · What is techum Shabbos? · תחום שבת בעברית