Either 18" or 22" available. We got these because of their comfortable ergonomic seat and for how easily it tilts into a recliner for someone who was immobile.  Got the first smaller one because the importer was out of stock for the 22" size with a 6 month delivery date. Then got the 22" roomier one later. (2023) They hold someone up to 300 lbs, Length 45", Width either 27.5 or 31.5" Height 50" or 55".  Both chairs reside in Yellow Springs, Ohio. They are the most comfortable and easy to use. We changed the front tire on the smaller one for easier turning and I notice that they now sell them with the wider tire. Good improvement. Front tires on the larger one are original.  Turning Radius 39", Weight 84 lbs, Cushion Thickness is 4" , The seat is discribed by the manufacturer as "Rehab Seat".   We found that my sister was always crooked in standard chairs, but in these chairs, it was easy to set her in a correct position.  That was a significant part of her longer periods in the chair.  Being able to tilt it for changing her pressure points was essential. Worth every penny.