Abstract: An apparatus for sizing bulk sandpaper to produce individual sandpaper sheets suitable for use in hand and powered sanders. A planar member, typically made of clear plastic is provided with a number of marked indicia indicating standard sizes for sander sheets. One or more sides of the planar member may be provided with a cutting edge whether attached to or molded onto the planar member. A handle is provided attached to the planar member to hold sandpaper in place for sizing. In use, a user places the device over a sheet of sandpaper on a workbench or the like and aligns the sandpaper to the desired size indicia. Applying mild pressure to the handle, the user may then tear or cut the sandpaper to the desired size. The apparatus may be economically made without multiple or moving parts and may be readily transported in a tool box, pail or the like.