Introduction

ID – the inner diameter of the pipe, which can be changed as per wall thickness. Whereas OD refers to the outside diameter of the pipe, it is a normally constant. The difference between the ID and the OD provides the wall thickness of the pipe. If you want to get the ID of the pipe, you can calculate it by subtracting twice the wall thickness from the total OD of the pipe.

What is difference between ID and OD?

ID

Assuming there is a hollow pipe, ID (inner diameter) is a measurement of the distance of a straight line from one point on the inner wall of the pipe, through its center, to another point also on the pipe’s inside wall. It depends on the pipe’s outside diameter and wall thickness.

When you measure the pipe from its inside, you will get a measured value called the ID (inner diameter).

OD

When it comes to the OD ( outside diameter) of the pipe, we all know it is the distance of a straight line from one outside edge of the pipe, through the pipe’s center, to an opposite on the outside. You can measure the cross-section that perpendicular to the pipe’s long axis directly.

When you measure the pipe from its outside, you will obtain another different measured value called the OD (outside diameter).

Conclusion

ID is inner diameter, the size of the hole in the pipe. While OD is outer diameter refers to the size of the pipe, including wall thickness.

If you required a pipe which is designed to use a size of 114.3mm threaded fitting.Whatever the wall thickness, the pipe must always have the same outside diameter with the threaded fitting. So you would ask for a pipe with an OD of 114.3mm.

If you use a pipe to transport water, the ID of the pipe must be large enough to accommodate the expected flow rate and volume. Otherwise, insufficient ID can lead to clogging and possible pipe failure.