The size is a perfect fit. However I don't know how they are rated for carpet thickness. This mat was rated for 'medium-pile' and I thought it would be extra heavy to use on my 'low-pile' carpet. It was not. Though rolling is easier it does dent if I sit in one position for for a minute or two also because it is so flexible even with the cleats the mat creeps. I'm concerned that the constant flexing will cause premature cracking.
This mat is heavy and I had high hopes for it doing the job. However indentations form under the chair castors so I periodically have to rotate the chair base to put the castors in a different position. Also the mat does not stay put on the thick carpet; periodically I have to move it back into position. I cannot spend more on a heavier -duty mat so I will probably keep it.
I kept this chair mat only because I used got it at a discount with a coupon and didn't want to hassle with taking it back. It is pretty small doesn't give much room to move your chair and it is not heavy enough to keep the chair wheels from denting into the carpet after you sit in one spot for a little so it is then hard to move the chair. I have another chair mat that I bought years ago that doesn't dent at all on the carpet wish I could find another one like it.
We purchased this mat after buying and returning one to a competitor which didn't fulfill our needs. This one is slightly better and will hopefully hold up over time. The delivery was a day later than promised (no big deal it could have been the freight company (FED EX) and doesn't affect the quality. The mat was rolled up and we laid it out on our living room floor for 2 & 1/2 days trying to get the mat to lay flat. We finally laid it out on our carpet in our sewing room under the sewing cabinet and after rolling the chair over it for a few days it has finally returned to laying flat. Our biggest concern is that the chair (with casters) and the sewing cabinet (also with casters) will eventually indent grooves in the mat. Only time will tell but so far so good. We've only had it less than to months.