Approx. measurements-  First measurement measures the lenghth from top to bottom and the second measures the width.

S- 25" x 14 1/2"

M- 25 1/2" x 15 1/2"

L- 26 1/2" x 16 1/2"

XL- 26 1/2" x 18"

XXL- 28" x 19 1/2"