First, determine the depth and breadth of the seat using a measuring tape. If using a back cushion, take the thickness of the back cushion into account when calculating the size of the seat cushion. Need to take this into consideration if the chair has an unusual form. Someone needs to take measurements of a square or rectangle that is contained within the unusual form. Around-the-clock comfort is provided by the materials responsiveness to heat, which cradles the body weight and softens the pressure spots. In addition to providing enough support for the lower back and buttocks, an ergonomic chair should also provide lumbar support.