What Size PVC is This?
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Time to read 3 min
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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 pvc 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 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.
Measure the Outside Diameter (OD): To identify your pipe size, measure the distance from one outside edge to the opposite outside edge across the center.
Use Nominal Sizing: PVC is labeled with "nominal" sizes (like 1" or 2"), which do not match the actual physical dimensions; for example, a 1-1/4" nominal pipe actually has an OD of 1.660".
Schedules Share the Same OD: Both Schedule 40 (white) and Schedule 80 (gray) pipes have the exact same outside diameter, meaning they use the same fittings regardless of their different wall thicknesses.
Material Matters: Standard PVC sizing differs from other materials like CPVC (which uses Copper Tube Sizing); always ensure your fittings match the specific piping system you are using.
FAQs
If I measure my pipe and it is exactly 2 inches wide, is it 2-inch PVC?
No. PVC pipe uses a "nominal" sizing system, meaning the name of the pipe doesn't match its exact measurement. For example, a 2-inch nominal PVC pipe actually has an outer diameter (O.D.) of 2.375 inches. If your pipe measures exactly 2 inches, it is likely a different size or type of tubing. Always compare your actual measurement to a PVC sizing chart to find the correct nominal size before ordering.
Do Schedule 40 and Schedule 80 PVC pipes use different sized fittings?
No, they use the same fittings. While Schedule 80 pipe has thicker walls than Schedule 40, both have the exact same outer diameter (O.D.). Because fittings slide over the outside of the pipe, a 1-inch Schedule 40 fitting will fit perfectly onto a 1-inch Schedule 80 pipe. The only difference is that the "hole" (inner diameter) of the Schedule 80 pipe is smaller because the walls are thicker.
Can I use standard PVC fittings with the cream-colored CPVC pipe in my home?
No. Standard PVC and the cream-colored CPVC (often used for hot and cold water lines in homes) use different sizing systems. Standard PVC follows Nominal Pipe Size (NPS), while most residential CPVC uses Copper Tube Sizing (CTS). A 2-inch PVC fitting is significantly larger than a 2-inch CTS CPVC pipe and will not create a secure connection. Always ensure your fittings match the specific material and sizing system of your pipe.
Mark Ligon
Mark Ligon is the marketing manager at PVC Fittings Online, a supplier of commercial PVC and CPVC pipe, fittings and valves. Ligon enjoys educating businesses on the parts of piping systems so managers can make informed decisions. He can be reached at webmaster@commercial-industrial-supply.com.
