Supply Fitting Connections

Trying to make sense of NPS, IPS, MIP, BSP, NPT and a half-dozen other fitting acronyms? We'll get you connected.


Supply Connections

Most of our faucets, showers, sprayers, etc. have NPS fittings, which is the standard connection for faucets sold in North America. However, there are many acronyms used for this common fitting. Many manufacturers (faucet, hose, supply line and/or adapters manufacturers) specify NPT, IPS, FIP/MIP and/or FPT/MPT fittings, but almost all are interchangeable; one primary exception – the fittings must NOT have tapered threads. Often, the "T" in NPT or FPT/MPT is used to represent "Tapered" instead of "Thread".

Due to the many acronyms for the same fittings and multiple definitions of specific acronyms, in North America, many faucet connections are often referred to simply as – 1/2" Faucet


NPS = National Pipe Straight
NPT = National Pipe Tapered
( -M = Male -F = Female )

Plumbing fitting are commonly referred to as “NPT”, however, in reality, nearly all faucets are actually “NPS”. NPS is the North American “STANDARD” for faucets, regardless of brand, style, application, etc. Outside North America, BSP is the most commonly used standard.

Both NPS and NPT have the same thread angle, shape, and pitch (threads per inch). However, NPS threads are straight (parallel) and NPT threads are tapered (reduced).

Straight Pipe thread is commonly found on faucets, showerheads, hose connections and fittings. Tapered Pipe thread is commonly found on pipe ends, nipples and fittings (i.e. couplings, elbows, tees, etc.). Straight Pipe threads need a gasket or o-ring to create a seal. Both styles require sealant or plumber’s tape for optimal seal. While NPS and NPT threads will engage, they do not seal properly with each other.


Acronym Definition Compatible with most Supply Connections
NPS National Pipe Straight
National Pipe Standard

NPT National Pipe Thread
National Pipe Tapered
National Pipe Thread (Tapered)

IPS International Pipe Size
International Pipe Standard
Iron* Pipe Size
Iron* Pipe Standard

FIP Female Iron* Pipe
Female International Pipe

MIP Male Iron* Pipe
Male International Pipe

FPT Female Pipe Thread
Female Pipe Tapered
Female Pipe Thread (Tapered)

MPT Male Pipe Thread
Male Pipe Tapered
Male Pipe Thread (Tapered)

GHT Garden Hose Thread
BSP British Standard Pipe
BSP is the standard fitting, adopted worldwide, EXCEPT in North America.

* Although it refers to “Iron”, actual material may differ. Today, iron is rarely used in plumbing, as it has been replaced with safer materials such as brass, stainless steel, PEX, PVC and other composites.

Still have a question? Send us an e-mail or give us a call!