From Halachipedia


  1. Mechateich is defined as cutting any item to a specific, desired size.[1]
  2. Mechateich applies to all materials. Nonetheless, Mechateich does not apply to foods.[2]
  3. In order to be chayav for Mechateich, one must perform the cutting in the usual manner, so if the cutting typically involves a tool, one will be patur if he performs the cutting with his hand.[3]
  4. Some say that it doesn't apply to cutting a utensil or a part of a functional utensil. Nonetheless it can be a violation of Makeh Bpatish or Kore'ah.[4]

In the Mishkan

  1. In the Mishkan, Mechateich involved cutting animal skins to specific sizes in order to sew them into coverings for the structure of the Mishkan.[5]

Practical Examples

  1. It is biblically forbidden to tear off a piece of aluminum foil, plastic wrap, or toilet paper from a long roll to a desired size.[6] Ripping not to a specific size is still forbidden under Kore'ah.[7]
  2. One violates this melacha by sharpening a pencil[8] or by cutting one’s hair or nails to a desired length when using the appropriate tool.[9] Biting one’s nails or cutting them off by hand would only be a violation derabanan.[10]
  3. One may tear along the perforated lines of small packets of sugar, salt, ketchup, etc., even though one is cutting to a specific size, because the true purpose of the cutting is to create an opening, and one tears on these lines simply because it makes it easier to open the package. When one cuts along the perforations, he merely intends that the contents from the package should not spill out, not to cut the packet to a particular size.[11]
  4. Some say that it is permitted to separate yogurt containers that are attached together and it isn't considered Mechataich or Metaken. Nonetheless, one who separates them before Shabbat will be blessed.[12]
  5. Some Sephardic poskim allow ripping the toilet paper off of the perforated lines since one isn't cutting it to a specific size. It is best to rip it with one's elbow or another shinuy. Obviously one should prepare before Shabbat and not get into this situation.[13]



  1. Mishna Brurah 322:18
  2. Mishna Brurah 322:18, Menuchat Ahava 3:21:5
  3. Mishna Brurah 322:18
  4. Menuchat Ahava 2:21:5
  5. 39 Melachos (v. 3, p. 931, 935)
  6. Mishna Brurah 340:41
  7. 39 Melachos p. 938 writes that cutting foil or plastic wrap to a measured size is Mechataich and when it is done without measuring it is Kore'ah. See Tiferet Mishna Brurah 322:15 citing Minchat Chinuch (Mosach Shabbat n. 33) who seems to be lenient.
  8. See Shabbos 75b where it states that one who drags the end of poles on the ground to sharpen them to a desired size is chayav for Mechateich. See also 39 Melachos (p. 935, note 3).
  9. 39 Melachos (p. 936, note 12). This is also a problem of gozez. The Minchat Chinuch in Musach Ha’Shabbos is quoted there stating that nonetheless Brit Mila is not a problem of Mechateich because the only reason we remove the orla is to fulfill Hashem’s commandment.
  10. See Mishna Brurah 532:1 where he states that biting and cutting one’s nails is irregular.
  11. Shemiras Shabbos Ke’hilchata 9:14 note 25, quoting R’ Shlomo Zalman Auerbach, and note 16. See also Rabbi Dovid Ribiat “39 Melachos” p. 937, note 16, where both reasons discussed in the above paragraph are quoted.
  12. Rav Shlomo Zalman Auerbach (Shulchan Shlomo 314:13:3), Yalkut Yosef (Shabbat v. 2, 314:30). Dor Hamelaktim v. 5 p. 3015 quoting Or Letzion 2:27:7, Halichot Olam v. 4 p. 254, and Nishmat Shabbat 322:354 who are lenient and Rav Elyashiv (Meor Shabbat v. 2 p. 551), Shevet Halevi (Kovetz Mbet Levi v. 6 p. 45), and Chut Shani v. 1 p. 128 who are strict.
  13. Yalkut Yosef (340:49, Shabbat v. 5 p. 146, 388)