Enter the maximum OD, minimum OD, and nominal OD into the calculator to determine the pipe ovality.

Pipe Ovality Formula

The following equation is used to calculate the Pipe Ovality.

O% = (MaxOD – MinOD) / NomOD *100

  • Where O% is the pipe ovality percentage (%)
  • Max OD is the maximum measured outer diameter of the pipe
  • Min OD is the minimum measured outer diameter of the pipe
  • Nom OD is the nominal OD of the pipe

To calculate the pipe ovality, subtract the max OD from the min OD, divide by the nominal OD, then multiply by 100.

What is a Pipe Ovality?


A pipe ovality is a ratio that measures how much a pipe appears to be an oval shape, or in other words, the measure of eccentricity with respect to the nominal diameter.

How to Calculate Pipe Ovality?

Example Problem:

The following example outlines the steps and information needed to calculate Pipe Ovality.

First determine the maximum OD. In this example, the max measured diameter is found to be 5 inches.

Next, determine the minimum OD. This is measured to be 4.50 inches.

Next, determine the nominal OD. The nominal OD is found to be 4.75 inches.

Finally, calculate the pipe ovality using the formula above:

O% = (MaxOD – MinOD) / NomOD *100

O% = (5 – 4.5) /4.75 *100

O% = 10.52%