The instructions say not to use it on thick carpet with a pad. However I couldn't find anything that would work better so this is what I bought. So far it is working fine. It does get indents but they come out after I leave my chair.
This pad would probably work fine on 1/4" carpet with no padding but consider a heavier weight mat for any thicker or padded carpet. Chair wheels tend to dent the mat when used on thicker or padded carpet.