I have to preface that I purchased these to fly.  I have to fly to and from Japan several times a year and I wanted something comfortable to wear.  Enter pajama jeans.  Not with that being said,  if I didn't want them to fly I wouldn't wear them.  They look more like navy blue sweats then anything else.  I'm a size 6 and I ordered a small.  They are a bit snug when you first put them on but other then that they seem fine.  I'm 5'2 so they are about a inch to long for me but if you are taller then 5'5 they won't it you.