The description lists the seat as 17.75x18. The 18 is actually the width. The 17.75 is actually less than 17.25 from front to back of seat bottom (depth) (pic 2). However, only 13.25 is usable for seating.  The other 4 is where the back attaches (pic 1), and it cannot be used for your behind. This makes the sitting area a little short and a bit uncomfortable. I was hoping these would be more comfortable for sitting at the counter for awhile, but they will be used as a quick fix until I can sell them and buy more. Thirteen inches on a seat cuts into the back of your leg for many people. My previous stools were 16 of usable sitting space so when these read 18 depth, I thought I had found the ones. Disappointed in false description of  measurements (most are not exact). Also, instruction pictures need much improvement.