When we measure PVC pipe, we measure the Inside diameter, and even then it isn’t exactly 1/2 inch or 3/4 inch.

Here are some photos and measurements to help you figure out what size you have!

You can also read more here: https://pvcfittingstore.com/pages/pvc-pipe-sizes-and-dimensions

After measuring, if you are still unsure, look at the listing from where you purchased your tumbler. They should be providing that information!

3/4 INCH PVC

Inside Diameter: about 0.0.824 inches inches

Outside Diameter: about 1.05 inches

1/2 INCH PVC

Inside Diameter: about 0.622 inches

Outside Diameter: about 0.84 inches

20 MM PIPE

This is not a standard US size. This is usually the pipe that comes with your amazon cup turners. Check the listing from amazon to be sure.