Draft educational material and decision-support only. A techum must be reviewed by a qualified rav or mumcheh.

What is techum Shabbos?

Techum Shabbos—also written tchum Shabbos or techum Shabbat—is the area within which a person may walk on Shabbos. The familiar starting measure is 2,000 amos, but determining where that measurement begins can require careful analysis of the surrounding dwellings and the shape of the halachic city.

Open the draft calculator

It is not simply a circle around an address

In open land, the place of shevisa is squared and the 2,000-amos measure is added on every side, including square corners. Inside or near a settlement, the starting boundary may instead depend on which dwellings join together, how nearby settlements relate, and how the resulting city is squared. The outcome can therefore differ from a simple radius drawn around a pin.

How this calculator builds a draft boundary

  1. Choose the place of shevisa. Search for an address and confirm the exact pin.
  2. Review mapped buildings. The tool obtains building footprints from OpenStreetMap and flags uncertain or ambiguous structures.
  3. Derive candidate settlements. It evaluates building chains and city-merger rules using the selected amah and halachic profile.
  4. Form the ribua. It constructs the city rectangle used as the measurement baseline.
  5. Add the techum. It draws the 2,000-amah boundary with square corners and exposes the intermediate geometry for review.

The same saved input and settings produce the same output. A snapshot can preserve the map data, settings, and manual building decisions so a reviewer can reproduce the calculation.

Why the line is always a draft

Public building data does not reliably say whether every structure is a halachic dwelling, and it can omit or misclassify buildings. Several measurement questions also depend on differing halachic approaches or case-specific judgment. The calculator highlights those uncertainties and offers documented settings; it does not decide them as psak.

Do not rely on an automatically generated line for practical walking. The Mishna Berurah 399:7 requires expert measurement. Bring the saved snapshot and visible audit layers to a qualified rav or mumcheh.

Common terms

Techum / tchum (תחום)
The Shabbos boundary measured from a person's place of shevisa or from the applicable city boundary.
Amah / amah (אמה)
The halachic cubit. Different accepted measurements change distances and can sometimes change which buildings connect.
Ibur ha'ir (עיבור העיר)
The process of evaluating and extending the city's edge before the techum is measured.
Ribua (ריבוע)
Squaring the place or city for techum measurement.
Eruv techumin (עירוב תחומין)
A separate halachic procedure that can shift a person's place for techum purposes. This calculator does not itself authorize or establish one.

Related spellings and searches

People use several English spellings for the same subject: techum Shabbos, tchum Shabbos, techum Shabbat, Sabbath walking boundary, 2,000 amos, and 2,000 cubits. In Hebrew, the central term is תחום שבת. This guide uses the variants naturally so readers can recognize that they refer to the same area of halacha.