To measure pipe size, you can follow these steps:
1. Determine whether you have a female or male threaded pipe, or no threads.
2. Find the outside diameter for male threaded pipes or pipes with no threads.
3. Measure the inside diameter if the pipe has female threads.
4. Divide the circumference by pi, or about 3.14159, to get an outside diameter measurement.
5. Convert your measurement to nominal pipe size (NPS). You can use a flexible measuring tape or string to measure the circumference of the pipe.
Here is a more detailed step-by-step tutorial on how to measure pipe size from [wikiHow](https://www.wikihow.com/Measure-Pipe-Size).
I hope that helps! Let me know if you have any other questions.
