Torah and Mitzvot

The answer to what will be the most popular question in synagogue tomorrow

Answer: Somewhere between 18″ and 24″.

Question: How big is a cubit, anyway?

This week’s Torah portion is the story of Noah and the ark. And as you’ll recall, when God gave Noah the instructions for building the ark, God specified the dimensions in cubits: 300 cubits long, 50 cubits wide, and 30 cubits tall.

I’ll let you do the math on the converting that to inches.

And if we really want to dig into the subject, here’s some more: The cubit system is based on the width of a human finger, which is 3/4″-1″ wide, and the handbreadth, which is four fingers, or 3″-4″ wide. A cubit is six handbreadths.

Many authorities hold that a tallis (prayer shawl) should be at least one cubit long on each side (a good contemporary authority on this is Rabbi Aryeh Kaplan and his book, Tzitzit). I almost included a cubit measurement conversion along with the metric conversion for the finished size of the tallit in the book. Using the 18″=1 cubit conversion rate, the dimensions would have been: 1 cubit by 3 cubits plus 3 handbreadths plus 1 1/3 fingers. It seemed like a fun idea, but in the end I decided that the handbreadths and all would be a bit much so I left it out.

For the record, that’s 18″ by 64″.

Shabbat shalom, everyone!

Maria BywaterMaria Bywater is the author of Sew Jewish, available in paperback at and Etsy and available for instant download in PDF format on Etsy. She teaches hands-on Judaica sewing workshops.