Published at Monday, November 04th 2019, 04:32:47 AM by Nancy Dior. Chair. These size designations have more to do with the chair user's height than weight. However, if a shorter chair user requires a wider seat or extra lifting capacity, wide chairs come in their own versions of Small, Medium, and Large, etc. That way someone who is short, but who weighs a lot will have a chair that fits more comfortably than a traditional sized lift chair made for someone much taller.