When shopping for clothes here at the Q, I always go to the "click here" garment measurements to compare XL and 1X sizes. Generally speaking, I find that 1X often has a little more room in the waist, but is slimmer throughout the legs. Also, 1X often has shorter sleeves, and a shorter armhole height, which is important for bra coverage on sleeveless tops. 1X sized tops usually have a longer length, so if I'm looking for coverage when wearing slim bottoms, I'll often go with the 1X. For the most part, I am usually fine ordering either size, it just depends on the fit I'm wanting from a particular item. HTH!