It's important to have the proper tools for measuring and marking as well as skill and accuracy in their use. The foot (') and the inch (") are the measurements used most frequently. Most measuring tools used in woodworking are divided into inches marked in halves, quarters, eighths, and sixteenths.

• Rulers: The ordinary 12-, 18-, and 24-inch rulers are used for measuring small projects, as they are more manageable than the larger rulers. They may be made of wood, plastic, or steel.
• Folding or zigzag rule: This wood or lightweight metal rule unfolds to 6 feet in length. It's used to measure distances where slight variations in measurement are not important.
• Steel tape: Available in lengths of 6, 8, 12, 50, and 100 feet, a steel tape ribbon is ordinarily used to measure distances too long to be measured conveniently with a folding rule.
• Steel or carpenter's square: A carpenter's square is an all-steel, L-shaped or two-arm tool that can be used to measure a board, test it for squareness, or check it for warping.
• Try square: The try square is composed of a steel graduated blade set at a right angle to a thicker beam of steel, plastic, or wood. The try square may be used to mark lines at right angles to an edge or surface, to determine whether a board is the same thickness throughout its length, and to test an edge or surface for squareness.
• Sliding T-bevel: Sometimes called a bevel square, the sliding T-bevel has at one end a steel blade from 6 to 12 inches in length, along with a 45-degree bevel point. The other, slotted end is fitted into a slotted wooden or metal beam or handle and held in place with a thumbscrew. The tool can be used to transfer angles from one piece of lumber to another and to test bevels.
• Combination square: The combination square is a steel graduated blade from 6 to 24 inches long. It is grooved along the entire length of one side. The blade is fitted to a metal head, which can be clamped at any distance along the blade. The square can be used as a try square, a depth gauge, or a marking gauge. It can also be used to check 45-degree angles and to test for levelness.
• Marking gauge: The wood or metal marking gauge is used to mark a line parallel to the edge or end of a piece of wood.
• Divider: A pair of pointed metal legs joined together at or near the top, a divider is used to describe circles or arcs, to transfer measurements from the work to the rule or from the rule to the work, and to mark lengths into equal parts.
• Carpenter's level: The carpenter's level is a 24-inch woodblock with true surface edges. It is used to determine whether a surface is level or an upright is plumb.
• Contour gauge: When a contour gauge is pressed against a surface with an irregular contour, each steel tooth slides backward to the extent necessary, thus forming an outline or template of the irregular shape. The opposite end of the steel teeth automatically forms a template of the same shape in reverse. The outline desired can be traced onto wood, paper, tile, linoleum, or any surface. A contour gauge is only 6 inches long; however, two or three of them can be joined together to make templates of wider areas.