A measuring tape is a flexible ruler used to measure distances on site. It is one of the most common tools in construction. The tape is a thin strip of metal or fiberglass with markings in inches, feet, centimeters, or meters. It retracts into a case with a spring. A locking mechanism holds the tape extended. A hook at the end catches on the edge of a surface. The tape is portable, durable, and accurate. It is the first tool a carpenter reaches for.

Measuring tapes come in several lengths. A 16-foot tape is standard for carpentry. A 25-foot tape is common for framing. A 35-foot tape is used for larger layout. A 100-foot tape, also called a long tape, is used for site work. The blade width varies. A wider blade stands out farther without bending. A narrower blade fits into tight spaces. The markings vary too. Some tapes have fractional markings. Some have metric and imperial. Some have a magnetic hook. Some have a blade with a nylon coating for durability.

Measuring tape accuracy depends on technique. The hook is designed to compensate for its own thickness. When measuring from an edge, the hook catches. When measuring from a mark, the hook slides. The user must pull the tape taut and read the mark at eye level. A sagging tape gives a long measurement. A twisted tape gives a short one. The tape must be kept clean and dry. A rusty tape is hard to read. The measuring tape is a simple tool. It is also a precision instrument. The whole building depends on it.