Question:
In a previous question the Rav dealt with the length of the beged for a tallis katan…what is the proper width of the beged?
Answer:
The proper width should be the same size and the length, which is an amah. See https://dinonline.org/2017/01/20/proper-shiur-for-adult-tzizis-length-and-width/ where the size of an amah was discussed.
Best Wishes
Sources:
M:B 16-7