What Size is this PVC Pipe?

Having trouble figuring out what size PVC pipe you're working with? Use this quick system for finding the nominal pipe size of your existing PVC pipe. It works for both Schedule 40 (white) and Schedule 80 (gray) PVC pipe!

To use the graphic above, first take a measuring tape and measure the diameter of the pipe at the center. This measurement should reach from the very edge of the outside of the pipe to the very edge of the opposite side. This measurement is called the "outer diameter".

Next, match that measurement up with the pipe size chart in the graphic. This chart includes sizes from 1/2" to 10". You'll notice, without a chart the dimensions could be deceiving. For instance you might assume a pipe with OD (outer diameter) of 1.660" is a 1-1/2" size pipe when in fact it is 1-1/4" size. That's why using a chart and understanding how PVC pipe sizes are measured is important.

Many PVC users think that 2" size pipe measures 2" exactly in diameter. Actually, 2" is just the nominal pipe size - meaning it is named 2 inch, but it in actuality it doesn't measure 2 inches. This system is a bit confusing and can lead to users ordering the incorrect size pipe and fittings for their project. Always check with a sizing chart before ordering if you aren't sure what size pipe and fittings you need.

Another misconception is that schedule 40 and schedule 80 PVC have different outside diameters. The truth is, the only difference is in the pipe thickness. The thicker schedule 80 PVC pipe has a smaller inside diameter to handle higher pressures, but the outside diameter remains identical to schedule 40 PVC pipe. That means all sch 40 and sch 80 pipe and fittings are interchangeable and will fit together.

The last thing you'll want to keep in mind is that PVC pipe uses a different sizing system than other types of pipe. For instance, the cream colored CPVC pipe you find in some homes uses what is called Copper Tube Sizing (CTS). These sizing differences are important to remember when buying fittings for existing pipe, as often times users don't understand how PVC sizing works. A 2" PVC fitting will not fit on a 2" piece of copper tube size pipe, but it will always fit on a 2" nominal size PVC pipe. The good part about this is if you are ordering PVC pipe and fittings you know they will always work together without any sizing issues. This is true across manufacturers and pipe schedules.