Tallit – Required Size
I have a Tallit which is long and narrow, which covers my head, shoulders and some of my upper body. It’s as large as a good pair of tzitzit. Is that big enough?
The Aish Rabbi Replies
Although the tzitzit we wear under our shirt can minimally cover most of our torso (see this past response), the tallit that we wear for prayers should preferably be large enough to cover most of our torso together with our head. This is because when we recite the blessing and first put it on, we wrap it around our head and body together. (Many cover their head with it for much of the prayers as well.)
Many people wear a tallit which covers their entire back or which reaches until around the back of their knees. But it shouldn’t be so long that the strings drag on the floor as that is considered disrespectful to the mitzvah.
Note that some people wear a long, skinny tallit which is not much larger than a scarf and which covers the neck and shoulders alone. It is doubtful if such a garment is obligated to have tzitzit at all, and it should not be used for the mitzvah.
(Sources: Shulchan Aruch O.C. 8:1, 16:1, 21:4, Mishna Berurah 8:3)