Shortees shirts come in two lengths, 25 inches and 26.5 inches. If you are under 5'6" try the 25 inch length; if you're between 5'6" and 5'8" go with the 26.5 inch length. If you are under 5'6" and like a slightly longer look you'll do great with the 26.5 shirt.
What size should you order? Shortees recommends that you order the same size t-shirt that you currently wear to fit your torso. If you wear large, order a large, if you wear medium order a medium. Length is chosen separately; either 25 or 26.5 inches.