How to Find the Square Inch of Pipe

Finding the area of a pipe's opening in square inches can be useful in determining the flow capacity of the pipe. A pipe with a larger opening allows more fluid to pass through and requires a slower flow rate than a pipe with a smaller opening. You can also use the square inches of a pipe for other calculations, such as determining the pipe's filled weight and finding the surface area inside the pipe.

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A pipe's opening can be measured in square inches.

Step 1

Use a tape measure to find the width of the pipe opening in inches. Do not include the width of the pipe wall.

Step 2

Divide the diameter by two to find the inside radius of the pipe opening.

Step 3

Use this formula to find the number of square inches in your pipe's opening: inside radius x inside radius x 3.1415.


Alan Sembera

Alan Sembera began writing for local newspapers in Texas and Louisiana. His professional career includes stints as a computer tech, information editor and income tax preparer. Sembera now writes full time about business and technology. He holds a Bachelor of Arts in journalism from Texas A&M University.