The short 20 x 5 x 4 in; the regular is 20 x 5 x 5.5 in. The packed sizes for the short are 20 x 4 x 5 in and 20 x 5 x 5.5 in for the regular.

Those are the packed dimensions, but the dimensions unrolled for the small are 51 x 20 x 0.75 in; the regular dimensions are 72 x 20 x 0.75 in.