This table includes the inside diameter (ID) and outside diameter (OD) measurements for Schedule 40 PVC pipes from 1/2 inch to 24 inches. Standard Specification for Poly(Vinyl Chloride) (PVC) Plastic Pipe, Schedules 40 ASTM

ASTM/ANSI SCH40 PVC Pipe SizeInside Diameter (ID)Outside Diameter (OD)
1/2 inch0.622 inches0.840 inches
3/4 inch0.824 inches1.050 inches
1 inch1.049 inches1.315 inches
1 1/4 inch1.380 inches1.660 inches
1 1/2 inch1.610 inches1.900 inches
2 inch2.047 inches2.375 inches
2 1/2 inch2.445 inches2.875 inches
3 inch3.068 inches3.500 inches
4 inch4.026 inches4.500 inches
5 inch5.047 inches5.563 inches
6 inch6.065 inches6.625 inches
8 inch7.942 inches8.625 inches
10 inch10.020 inches10.750 inches
12 inch11.938 inches12.750 inches
14 inch13.124 inches14.000 inches
16 inch15.000 inches16.000 inches
18 inch16.876 inches18.000 inches
20 inch19.562 inches20.000 inches
22 inch21.562 inches22.000 inches
24 inch23.250 inches24.000 inches

How to choose the right size PVC fittings for my pipe?

For example, if you have an 1/2 inch sch40 pvc pipe, the outer diameter of the 1/2 inch PVC pipe is 0.840 inches, so the corresponding inner diameter (ID) of a fitting designed to connect with this pipe would typically be slightly larger than the pipe's outer diameter to allow for proper fitting. A common allowance is to have the fitting's inner diameter approximately 1/16 to 1/8 inch larger than the outer diameter of the pipe it is intended to connect to.

So, for a 1/2 inch PVC pipe with an outer diameter of 0.840 inches, the corresponding inner diameter of a fitting might typically is 0.85 inch or 21.6mm.

1/2 in. sch-40 pvc 3-way fitting from 247Garden

What if I have a 3/4 inch sch40 pvc pipe, what is the proper size fitting for it?

For a 3/4 inch Schedule 40 PVC pipe with an outer diameter of 1.050 inches, the corresponding fitting should have an inner diameter (ID) that allows for a snug fit over the pipe. As with the previous example, a common allowance is to have the fitting's inner diameter approximately 1/16 to 1/8 inch larger than the outer diameter of the pipe.

So, for a 3/4 inch PVC pipe with an outer diameter of 1.050 inches, the corresponding fitting should be a little bit over 1.050 inches. For the perfect size sch40 3/4 pvc fitting, you can check out all the ASTM ANSI fittings from 247Garden.