What size is schedule 10 pipe?

Schedule 10 pipe refers to a classification of pipe wall thickness. The term "schedule" refers to the wall thickness of the pipe, and schedule numbers are a standardized way to specify that thickness. The size of a Schedule 10 pipe varies depending on the pipe's nominal diameter (NPS - Nominal Pipe Size).

Here are some examples of Schedule 10 pipe sizes:
1/2 inch NPS: 0.840 inches outside diameter (OD), 0.065 inches wall thickness
1 inch NPS: 1.315 inches OD, 0.109 inches wall thickness
2 inch NPS: 2.375 inches OD, 0.154 inches wall thickness
4 inch NPS: 4.500 inches OD, 0.237 inches wall thickness
6 inch NPS: 6.625 inches OD, 0.280 inches wall thickness
10 inch NPS: 10.750 inches OD, 0.365 inches wall thickness

The wall thickness increases as the nominal pipe size increases, but for each nominal size, the wall thickness for Schedule 10 is consistent. The OD remains the same for a given nominal size across different schedules, but the wall thickness and, thus, the inside diameter (ID) will vary.