How to Calculate Developed Length in Plumbing

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Things You'll Need

  • Tape measure

  • Pencil and paper

PVC is a common material used to construct pipes for plumbing.
Image Credit: Comstock/Comstock/Getty Images

The length of a pipe that is used in plumbing is an important calculation. This measurement helps plumbers to calculate the amount and cost of supplies needed for a project. Pipe length also is an important consideration when it comes to water pressure. The developed length of a pipe is a measurement that is conducted along the center of a pipe. This plumbing measurement also takes into account the lengths of the fittings on either end of the pipe.


Step 1

Align a tape measure along the center of a pipe and measure the pipe's length. Write down the measurement. For example, the pipe might be 8 inches long.

Step 2

Write down the appropriate measurement for the fitting that is used on the specific type of pipe. For example, the socket depth for a 1-inch plastic pipe is 3/4 inch.

Step 3

Multiply the fitting measurement times 2 to account for the fittings on either end. Using the previous example of a 3/4-inch fitting, you would multiply 3/4 times 2 to get 1 1/2 inches.


Step 4

Add your answer from Step Three to the length from Step One to get the determined length of the pipe. In this example, you would add 1 1/2 to 8 to get a determined length of 9 1/2 inches.



Charlotte Johnson

Charlotte Johnson is a musician, teacher and writer with a master's degree in education. She has contributed to a variety of websites, specializing in health, education, the arts, home and garden, animals and parenting.