Is XL the same as 1X? Is XXL the same as 2X? No!
Straight sizes are written in the form of XS, XL, or XXL. These sizes all have a similar hip to waist ratio.
1X and 2X are plus sizes that are built to fit a fuller waist, which is more common in plus size body types. In addition to a different hip to waist ratio, plus size grading also accounts for the way that other proportions change as size increases.