Pipe Size & Fitting Chart
Pipe and pipe fitting sizes from 1/8 in. to 4 in.: the actual outside diameter, NPT threads per inch, and Schedule 40 and 80 inside diameters, with an example fitting Supply Tie stocks in each size in black or galvanized malleable iron, PVC and brass.
How pipe sizes work
- Nominal size is not a measurement. A "1/2 in." pipe has an outside diameter of 0.840 in. Measure the outside of the pipe and use the table to find its nominal size.
- Same size, same outside diameter. Steel, iron and Schedule 40 or 80 PVC pipe of the same nominal size share the same outside diameter; the schedule changes the wall thickness and the inside diameter. Threaded fittings fit threaded steel, iron and Schedule 80 PVC pipe. Schedule 40 PVC should not be threaded and uses solvent-weld (slip) fittings.
- NPT threads are tapered. National Pipe Taper threads seal as they tighten; use thread sealant or PTFE tape rated for the job (gas-rated sealant on gas lines). MIP/MPT is male thread, FIP/FPT is female thread.
- Copper and PEX are different. Copper tube and PEX are sized by a different standard, so their outside diameters do not match iron pipe of the same nominal size. Use adapters to join them.
Pipe size chart (1/8 in. to 4 in.)
Shop pipe fittings
- STZ Industries black and galvanized iron fittings
- Charlotte Pipe PVC pipe and fittings
- ATC brass fittings
- Industrial pipe fittings and hydraulics
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