Drywall squares provide a measuring stick and straight edge for scoring drywall, plasterboard, and other materials. Also known as drywall T-squares, their crossbar head holds them in place along the edge of material while making the cut. These squares are generally larger and more resistant to rough use than drafting T-squares.

T-squares have a graduated blade with a crossbar head that holds them in place along the edge of a drafting table or other surface when making horizontal lines to a specific length in technical drawings. Pairing these drafting T-squares with a set square allows drawing vertical and diagonal lines, and their blade also serves as a straight edge for guiding cuts.