Leggings and tights are very similar in that they are skin-tight garments that cover the legs and sometimes the waist. Leggings are much thicker, footless, and can sometimes be worn like pants. Tights are somewhat sheer, cover the foot, and must be worn under another garment.
A big question comes in which is the distinguishing factor – transparency or feet. Usually transparent garments without feet are called "footless tights," though some manufacturers refer to them as leggings.
Neither leggings nor tights, however, should be confused with stockings, which are more like socks that go all the way up to the thigh, and unlike tights or leggings are not joint at the seam.
Design
Leggings are made from thick, elasticized material, usually spandex, lycra, nylon, cotton, and/or polyester. Their length is from mid-calf to the ankle. Some leggings are designed more similar to tights - smooth around the waist and lower torso, while some are more similar to pants - they may feature a distinct waist, pockets and reinforcement in the crotch.
Tights are made from elasticized material, usually cotton or polyester blends. Tights cover from legs to toe tips, with some cutting off at the thigh (called thigh highs) and others covering up to the waist. They are smooth throughout, though control top styles are tighter in the lower torso. Because they are at least semi-transparent, they are designed to be worn under clothing.
Fit
Leggings are designed to fit snug, shaped to fit the contour of the body - and they are still very comfortable. Tights are designed to fit extremely tight, like a second skin. They are similar in comfort to nylons, which are not considered very comfortable.
Style
Leggings are casual. They are often worn during exercise. Dressier leggings may be worn in place of pants and under tunics. It is possible to wear leggings under skirts and dresses.
Tights range from casual to professional. They are worn under another garment, such as skirts, dresses or even shorts.
Appearance
Leggings come in a wide range of colors and patterns. Very cheap leggings may be translucent. Otherwise, they are usually not sheer.
Tights also come in a wide range of colors, but fewer patterns than leggings. They usually have some level of transparency, though this may not be the case with wool tights.
Care
Unless otherwise specified, leggings can generally be laundered the same way as pants, taking no special care. Tights should be laundered with care, similar to washing nylons, preferably in mesh bags.
