The straight edge ruler, also known as a bench rule, is an implement used to draw and cut extremely accurate straight lines. This is done by running a pencil or other writing instrument, or a cutter or blade, along the edge. Generally, measures are mainly used to calibrate length and straight edge rulers are most often used for drawing or cutting lines. In this respect, straight edge rulers differ to measures in their purpose but many rulers have gradations for measuring and can also be used as measures.

Straight edge rulers range in length from a short 15 centimeters to 2 meters. They can be made of a number of materials but steel types can produce perfectly straight lines with relatively little pressure because of their weight. Being hard, they are also very useful as a guide for cutting. Aluminum types are easier to handle because they are lighter but the corners can get crumpled by impact if they are dropped. They are also ideal for use with blades. Because plastic and acrylic types are transparent, it is easy to see through them and, therefore, they are also easy to use, but in a different way to the metal types. (Some types also have grids.) Bamboo types are light, strong and flexible while wooden types are fairly thick and can be used for folding paper. Some straight edge rulers have a groove for drawing channels. Folding rulers have joints in several locations and are convenient for carrying around.

When using a cutter, metal rulers are preferred. If they have gradations on one side only, the cutting should be done from the other side. Some acrylic rulers have a stainless steel edge for use with blades, which should be used when cutting. Avoid direct contact between the blade and the wooden part or the side with no edging. With block prints, cutters are not used on the paper. Instead, the straight edge ruler is placed on the paper and the paper is torn off by hand along the ruler. This achieves a natural appearance on the transverse section. When using ink, pens or some other form of writing instrument, it is better to invert the angled, gradation side of the ruler to prevent the ink from smudging. Straight edge rulers can be purchased at art supply, stationery stores, etc.