A Pi Tape (sometimes spelled "P-I-Tape") is a precision measuring tool that is used to measure the circumference of circular objects such as pipes, tubes, and rods. It is also known as a "circumference tape" or "pipe measuring tape".

The Pi Tape is a flexible steel tape measure that is coated with a thin layer of plastic or other material to protect the steel from corrosion. The tape measure is marked with measurements in inches and millimeters and has a spring-loaded retraction mechanism to keep the tape measure tight against the object being measured.

The Pi Tape is most commonly used in industries such as plumbing, HVAC, and industrial manufacturing, where precise measurements of pipe and tubing diameter are required. It is also used in other industries such as automotive and aerospace, where it is important to measure the circumference of tubes and rods.