I bought several pair of this brand on the same day, also the convertible legging. The quality is top notch. I would buy the size you normally buy in leggings. I absolutely disagree with reviews saying to buy a size up is. I normally buy small in leggings but went to a medium in both pairs. Medium works but could have gone small. I wear these  under thin leggings that have a style. All in all, I am a fan and will buy more.