They usually run a little small, but their colored skinny jeans run HUGE! I usually wear a size 18 in pants, now due to f21’s usual habit of making everything small, I tried a pair of size 20 pants and they were so loose they fell off my butt and looked like mom jeans! The size 14 fits snug and the size 16 fits and could be washed in hot water.
In short, everything you know about f21 sizing does NOT hold true for their colored jeans. Holy moly!