Different sources have different information regarding the size of an Amah (all measurements are attributed to Chazon Ish):

  • Halachipedia - 24 in. / 60.96 cm

  • Dafyomi.co.il - 22.72 in. / 57.72 cm

  • Daat.ac.il - 22.68 in. / 57.6 cm

  • Artscroll "Gateway To The Talmud" - 22.8 in. / 58 cm

  • Wikipedia - 22.56 in. / 57.3 cm (although 57.6 cm if multiply from Etzbah)

  • Steinsaltz Talmud Guide - 22.7 in. / 57.6 cm

I believe the source of the Chazon Ish's opinion is OC Moed 39 - Kuntres Hashiurim. My Hebrew is not great, but it seems to mention 58 cm a few times throughout.

Why do so many sources have different numbers for the same authority's opinion? Which source has the most reliable information that goes in accordance with what the Chazon Ish says?

  • 1
    I'd guess it has to do with rounding a smaller unit (tefach? etzba?) and then multiplying up to an ammah.
    – Double AA
    Jun 15, 2020 at 13:21
  • @DoubleAA Thanks for the response. There are multiple versions for etzbah as well: 2.4cm (Daat, Wikipedia), 2.405 (DAF), 2.413 (Artscroll), and 2.54 (Halachipedia). Halachipedia seems to be far off from the others and 2.4 could be a rounding result. If rounding errors are causing the issue, I think Artscroll is most plausible, but I'd like to figure out what Chazon Ish actually said. Jun 15, 2020 at 15:36

1 Answer 1


In the Steipler's Shiurin shel Torah he writes the Chazon Ish's opinion about the amount needed for each Mitzvah. When it is a Mitzva D'Oraisa like Sukkah, he uses 10cm as a Tefach - 60cm as an amah enter image description here, but when it is a question of a D'Rabannan as seen in the topic of Ma'aka/fence on a roof (in a D'Rabbanan situation b'shas ha'dchak) he uses 9.6cm as a tefach - 57cm as an amah he uses 9.6cm as a tefach - 57cm as an amah.

  • Thanks for explaining the source! Do you have an idea how the numbers such as the commonly seen 57.6cm and Artscroll's 58cm came about? Jun 15, 2020 at 17:59
  • 1
    @eyl327 If you round off 9.62 to 9.6, times 6 = 57.6, and if you round off 9.82 to 9.8, times 6 = 58.8. Jun 15, 2020 at 18:24
  • 3
    Shame they don't cover sig-figs in semicha classes
    – Double AA
    Jun 15, 2020 at 23:39

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