Plumbing and Fittings

Need Help Identifying the Size of Your PVC Piping?

The size of your PVC pipe is identified using the inside diameter measurement of the pipe - this measurement is known as 'Nominal'. One of the issues that is commonly encountered when trying to measure pipe size is that the outside diameter of the pipe is often measured, giving you a completely different (and larger) PVC pipe dimension then what you actually require.

If you are going to measure the outside diameter of the pipe, take the following steps:

1. Take your outside diameter measurement, and then refer to the tables below for the Actual Outside Diameter
2. Once you find the actual outside diameter of the pipe in the chart, then look at the Pipe Size beside it - this will be the nominal pipe size, which gives you the size of fittings you want to order

Actual Outside Diameter

The measurement of the pipe from top to bottom, or left to right.
Taken from the outside edges of the pipe section.
This measurement is not your PVC pipe size.

Average Inside Diameter

The measurement of the pipe from top to bottom, or left to right.
Taken from the inside opening of the pipe section.
This measurement is equal to your PVC pipe size.

Pipe Wall Thickness

The measurement of the thickness of the PVC pipe.
Taken from the outside to the inside of the pipe section.
This measurement changes between each Schedule of PVC piping.

PVC Schedule 40 Sizing Table

Schedule 40 PVC pipe is compatible with all external fit and internal fit fittings.

PVC Schedule 80 Sizes Table

Schedule 80 PVC pipe is only compatible with external fit fittings. Internal fit fittings, such as Internal Dome Caps, Adjustable Elbows, Internal Couplings and other fittings that fit inside of the PVC pipe will not work with SCH 80 PVC due to the smaller internal diameter.

PVC Thinwall Sizes Table

Thinwall PVC pipe is only compatible with external fit fittings. Internal fit fittings, such as Internal Dome Caps, Adjustable Elbows, Internal Couplings and other fittings that fit inside of the PVC pipe will not work with Thinwall PVC due to the larger inner diameter.

Not all sizes are available in Thinwall PVC pipe.