Abstract: A device for estimating the length of the floor covering needed from a roll of floor covering having a predetermined width to cover a room, including any fill area based on a scale diagram of the room showing walls bounding the room. The device comprises a generally planar body having an upper surface and opposing lower surface for contacting the diagram. A first positioning guide is provided on the body for aligning the body on the diagram about a first direction. A second positioning guide is provided on the body for aligning the body on the diagram about a second direction. Floor covering width and length indicia are provided on the body along the first and second axes, respectively. A fill width indicia is provided on the body and corresponds to the first direction. A data matrix comprising multiple cells is defined by the intersection of the fill width indicia and the floor covering length indicia.