This is the 2nd pair I purchased. This time I bought my street size (6) which is a small in these thermal pants. I returned one because based on some reviews I sized up. Those were a large & I exchanged for a medium and were still baggy in the legs and about a pull of the waist of 1.5-2”. I ordered these in the small and perfect for my body type. I am 5’4” and weigh 133-135. I have slim legs, flat backside, and very little tummy. I do have what I call a wide or thick waist so the elastic in the back saves any issues in that area. I do tuck them in my winter boots as I agree with others the legs are too narrow to fit over a bulky boot. That doesn’t bother me though. These are well constructed in my opinion. I wore the medium with a fleece lined tight when it was -5 but no wind. I was actually too warm but also had on a very warm long jacket. My plans are to wear in late fall and winter to clean up the yard and scoop snow off my deck.