average petite inseam
Average lengths for inseams in women's clothing: 31 or 32 for Regular. 28 or 29 for Petite. 34 for Tall. 36 for X-Tall. Sometimes it's a half in not a full. Like 31 1/2 on the regular. I don't know about Gap size charts, but I would guess that xlong would be around a 36 inseam.