Difference Between NPT and MIP (2023)

All pipes are connected with fittings, which allow connection of pipes along a straight run, called couplings. There are different types of fittings used to connect pipes, like 90 degrees couplings or elbows, 45 degrees angles, T fittings, and a wide range of other formats. In PVC, often slip fittings are used which are glued together. Some fittings are threaded which are called threaded fittings. These are screwed into compatible connecting fittings in pumps or other plumbing works. The NPT standard is most commonly used in the United States for many different applications such as pumps, fuel systems, regulators, filters, and so on. The MIP is also used interchangeable with the NPT.

Difference Between NPT and MIP (1)

National Pipe Taper (NPT)

NPT, or National Pipe Taper, is a US standard for tapered threads used for joining pipes and fittings. It is an American standard thread on malleable iron pipes, which have a slight taper. The NPT standard includes a slight tapering between the male and female connections. Fittings with male (external) threads are often referred to as MPT (Male Pipe Thread) or MNPT (Male National Pipe Thread), and those with female (internal) threads are called FTP (Female Pipe Thread) or FNTP (Female National Pipe Thread). An American businessman and mechanical engineer, William Sellers invented a uniform system of screw threads which later became the NPT standard in 1864. The most common material used is iron and brass, which are commonly used for low pressure applications whereas stainless steel and carbon are mostly used for high pressure applications.

Difference Between NPT and MIP (2)

Male Iron Pipe (MIP)

MIP, or Male Iron Pipe, is one of the two commonly used components in heavy duty threaded pipe connections. Male iron pipe, as the name suggests, is a pipe wit threads on the outside, such as a pipe nipple. FIP (Female Iron Pipe) fittings, however, has threads on the inside. MIP is a pipe fitting with NPT threads and is commonly made of stainless steel and brass. Although the name says iron, MIP fittings are not always made of iron. If one side of the fitting is MIP and other side in FIP, it’s usually called mip by slip. MIP fittings are mainly used in conjunction with FIP fittings is many different ways in commercial, residential and industrial piping systems. They are used in heavy duty applications such as high pressure pipe systems or natural gas carrying pipes. A couple of different materials are used to make MIP fittings depending on application areas.

Difference between NPT and MIP


– NPT refers to both internal and external threads on fittings that conform to the ANSI/ASME B1.20.1 standard pipe threads. National Pipe Thread Tapered, or NPT is the US standard for tapered threads used to join pipes and fittings. MIP, on the other hand, is the acronym for male iron pipe and is a pipe fitting with NPT threads. MIP refers to fittings with male threads and FIP describes fittings with female threads.


– NPT threads are commonly made from PVC and plastic whereas MIP pipe fittings are commonly made from stainless steel and brass. Other materials are also used for MIP fittings such as iron, copper, PVC, plastic, and so on. Metal pipes with threads are much durable and sturdier than the non-threaded ones. Thus they can withstand accidental damage and chances of pipe wear and tear from daily use are less. Plastic threads are relatively less durable and are more prone to leaks.


– NPT fittings are mainly used for low pressure applications like residential pipe systems and hydraulic systems. Many industries use NPT fittings for sealing pipes for gas and fluid transfer. They are used in a wide range of pressure sensitive applications, ranging from electrical conduits to high pressure pipes that carry natural gas and chemically aggressive liquids. MIP pipes are used in high pressure applications in a variety of industries as well as in residential pipe systems.

NPT vs. MIP: Comparison Chart

Difference Between NPT and MIP (3)


In a nutshell, NPT is the defined standard for pipe fittings regulated by the American National Standards Institute (ANSI) and is approved for use in residential and commercial piping systems. But many people NPT and MIP interchangeably. MIP is a pipe fitting with NPT threads. Fittings with male threads are called MIP whereas fittings with female threads are called FIP. NPT and MIP work together but do not mate with any other type of fitting. NPT fittings are mostly used in residential and hydraulic systems, and male iron pipe is used in a wide range of applications, including commercial and residential pipe systems.

Can you connect NPT to MIP?

NPT and MIP work together but do not mate with any other type of fitting. They have similar thread dimensions, so both the fittings are interchangeable.

Is MIP fitting tapered?

MIP threads are not tapered. There is no tapering on either side of the pipe.

Is MIP and MPT the same?

MIP stands for male iron pipe whereas MPT stands for male pipe thread. Both are pipe fittings with NPT threads. MPT is a sub type of NPT and MPT/FPT and NPT threads are not compatible.

Are MPT and NPT threads compatible?

No. MPT and NPT threads are not compatible.

What is a MIP fitting?

MIP is a pipe fitting with NPT threads. Fittings with male threads are called MIP and fittings with female threads are called FIP.

What does MIP mean in plumbing?

MIP is one of the major components in heavy duty threaded piping connections. MIP has threads on the outside and a FIP fitting has threads on its inside like a T fitting.

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Is MIP compatible with NPT? ›

NPT, MIP, and FIP work together but do not mate with any other types. An NPT will not fit a BSP. You can force threads together, but if they don't completely match, then your fittings won't seal. Most pipe thread types are not interchangeable.

Is NPT and MPT the same? ›

​NPT. NPT stands for National Pipe Thread and is an American standard thread. It may also be reffered to as MPT , MNPT or NPT (M) for male external threads and FPT, FNPT or NPT(F) for female interal threads. A thread sealant must always be used to achieve a leak free seal (except for NPTF).

Is MIP and MPT the same thing? ›

Other Notes About Thread Sizing

As previously mentioned, NPT indicates the defined standard from ANSI - but many people use MPT/MIP and FPT/FIP interchangeably. MPT stands for Male Pipe Thread and MIP stands for Male Iron Pipe which both indicate a male fitting with NPT threads.

Are NPT and MPT compatible? ›

MPT is a sub-type of the NPT thread and is interchangeable with NPT.

Do NPT threads need sealant? ›

NPT pipe thread design allows slight clearance between the thread crests and mating roots. This clearance creates a spiral leak path along the male thread crests. The spiral leak path is why NPT connections require a thread sealant to be leakproof.

Should you use Teflon tape on NPT? ›

Teflon tape makes a good, leak-tight seal in NPT fittings, but the tape can introduce contamination and if not wound properly, can reduce proper sealing as well. The NPT thread lubrication takes the form of plumber's tape, although sometimes a semi-liquid putty is used, albeit less popular in fluid power.

What are the 3 basic types of threads? ›

There are three standard thread series in the Unified screw thread system that are highly important for fasteners: UNC (coarse), UNF (fine), and 8-UN (8 thread).

Is PEX a NPT? ›

PEX x Female Threaded Adapters allow to create a straight transition between PEX tubing and threaded pipes. Threaded side is female NPT (FNPT). These brass crimp style PEX fittings are compatible with Crimp and Clamp (Cinch) connection systems.

How do I know if thread is NPT? ›

As a general “rule of thumb” an NPT thread is approximately 1/4" (0.25”) larger than its “name.” For a 1/4" NPT fitting the “nominal” OD is 0.533”. NPT fittings are slightly tapered so the “nominal” diameter is the diameter in the middle of the threaded portion, as measured by the top (crest) of the threads.

Are NPT threads tapered? ›

NPT has a tapered male and female thread which seals with Teflon tape or jointing compound. Pipe threads used in hydraulic circuits can be divided into two types: Jointing threads are pipe threads for joints made pressure tight by sealing on the threads and are taper external and parallel or taper internal threads.

What does 3 4 NPT mean? ›

The 3/4" NPT pipe thread has 14 threads per inch. Both the TPI (threads per inch) and OD (outside diameter) of the thread are required for positive identification of thread size because several sizes have the same TPI.

What does NPT thread stand for? ›

NPT (National Pipe Taper) Sizes: BSPT (British Standard Pipe.

How do I know what NPT fittings I have? ›

NPT fittings are listed by the "standard" inner diameter (I.D.) of the fitting. (We put "standard" in quotes because the I.D. of the fitting will vary, depending on the manufacturer.) The outer diameter (O.D.) of the threads is usually about 1/4 (0.250) in. larger than the stated I.D.

Who uses NPT thread? ›

Tapered pipe connections are favored in a wide variety of industries, including power plants, chemical, oil and gas, manufacturing and shipping. The NPT standards are divided into two categories: National Pipe Tapered (also NPT) and National Pipe Straight (NPS).

Does NPT work with universal thread? ›

The male threaded ends connect to NPT, NPTF, BSPP, BSPT, and other universal threads, so you don't have to bother matching exact thread types.

What are the disadvantages of NPT threads? ›

Cons of Using NPT Pipe
  • Fitting may crack due to overtightening. That's why you need to carefully follow the installation tips below.
  • ​Requires sealant, which can potentially contaminate a fluid system. ...
  • Unsuitable for high-pressure systems. ...
  • Sealing performance decreases with size.

How many times do you wrap Teflon tape? ›

When applying the tape clockwise, it's recommended that you wrap it around the thread three or four times. This is thick enough to prevent leaks, but not too thick that you can't get the nut on.

How tight should NPT threads be? ›

This is because the torque applied to correctly tighten an NPT fitting will vary with thread quality, material and which type of sealant is applied. Generally, correct tightening is achieved by first tightening finger tight (until the thread seats), followed by 1.5 – 2.5 full turns with a wrench.

Can too much Teflon tape cause leaks? ›

If the tape is wrapped in a counterclockwise direction (or against the direction of the thread) it will unravel when mating into the female connection. Also, do not use too much Teflon tape as this could be counterproductive and prevent the joint from sealing properly and/or causing the tape to gum up.

What do plumbers use instead of Teflon tape? ›

When it comes to sealing pipe threads there are typically two tools that are plumber will use. The first is pipe joint compound, more commonly known as pipe dope, and the other is Teflon tape. While both tools do a job of creating a secure seal, each one has its own unique advantages.

Can I use silicone instead of Teflon tape? ›

Luckily- there is a better way. Even better news is that there are TWO better ways. The better, safer, more efficient way to ensure seal integrity is to use Engineered Silicone Formulations and in some instances- Teflon-Bonded Silicone.

What is the most commonly used thread type? ›

Metric thread is the most widely used today, and can otherwise be referred to as 'ISO Metric' or 'M'. Both coarse and fine thread fasteners are available, and can be supplied in a wide range of materials and sizes – with a number of popular DIN standards.

What type of thread is best for threading? ›

Using high-cotton sewing thread will ensure your eyebrow hairs do not snap off between the thread. High-cotton thread tends to grip hair better than synthetic thread. Thread is the best thing to use for threading.

Which type of thread has highest strength? ›

Size for size, a fine thread is stronger than a coarse thread. This is both in tension (because of the larger stress area) and shear (because of their larger minor diameter). Because of the smaller pitch, they allow finer adjustments in applications that need such a feature.

Can I use blue PEX for hot water? ›

Color-Coded: Red PEX pipes can be used for hot water supply lines, blue PEX for cold water supply, and white for either hot or cold. These colors are just for your convenience. Plumbing code does not require the pipe color to match the type of water supply.

Is SharkBite PEX type A or b? ›

SharkBite non oxygen barrier pipe is manufacture as PEX-B and SharkBite oxygen barrier pipe is manufactured as PEX-C.

Can you run PEX through PVC pipe? ›

And fortunately, connecting PVC to PEX is easy to do. Whether you're looking to repair or expand your plumbing, adding PEX to your existing system is accomplished using a threaded fitting. In general, a fitting comes with one half to attach to existing pipe, and another half that fits on the PEX pipe.

What is the best way to seal NPT threads? ›

Two of the most commonly used methods for sealing metal pipe threads are anaerobic pipe thread sealant and PTFE thread sealant tape. To apply PTFE thread sealant tape sealant on a pipe, you wrap the male pipe in the direction of the thread tightly.

How do I tell what type of pipe thread I have? ›

To identify whether the thread is tapered or parallel, look at the diameter of your thread. If the thread diameter gets thinner towards the end, you are looking at a tapered thread. On the contrary, if the thread diameter is the same at the top and the bottom of the thread, you have the parallel thread.

Can you reuse NPT fittings? ›

Though the same function does not happen with NPT fittings, it is not recommended that NPT fittings be reused. Overtightening is common, particularly when a fitting is reused, which can cause galling or increase the likelihood of leakage.

Will a 3/4 NPT work with a garden hose? ›

The 3/4" Brass Female Connector is the quick and easy way to connect any irrigation or misting system to a simple garden hose or hose bib.

Is the garden hose 3/4 NPT? ›

Garden hose adapters and connectors are fittings that have a standard 3/4" garden hose thread (GHT) connection on one end and a connection with a different thread type on the other end, such as National Pipe Taper (NPT). They securely connect garden hoses to a pipe, valve, or accessory that has a different thread type.

What size hole do I drill for a 3/4 NPT tap? ›

NPT Tap Drill Chart
Tap SizeDrill SizeTap and Drill Set
3/8" NPT Tap37/64" Drill Bit3/8" NPT Tap and Drill Set
1/2" NPT Tap23/32" Drill Bit1/2" NPT Tap and Drill Set
3/4" NPT Tap59/64" Drill Bit3/4" NPT Tap and Drill Set
1" NPT Tap1-5/32" Drill Bit1" NPT Tap and Drill Set
10 more rows

Why are NPT threads tapered? ›

Tapered threads help make better seals. The male and female threads compress and wedge themselves together. As a result, these connections are stronger and leak resistant. NPT pipe thread is the most common tapered pipe thread used in the United States and Canada and is incompatible with BSPT pipe threads.

Is NPT same as garden hose? ›

Garden Hose Thread (GHT) comes male (MGHT) and female (FGHT). It's important to note that GHT is different from NPT. Garden hose connections are not compatible with NPT even though both are threaded.

Can NPT and NPS be used together? ›

While NPT & NPS threads will engage and seem like they fit - they will not seal properly with each other causing leaks.

Can I connect an NPS to an NPT? ›

Thread sealant or tape is typically required to complete the seal. Straight pipe threads need a gasket or O-ring to create a seal. While NPT and NPS threads will engage, they do not seal properly with each other.

Does a universal thread work with NPT? ›

The male threaded ends connect to NPT, NPTF, BSPP, BSPT, and other universal threads, so you don't have to bother matching exact thread types.

What fits in NPT threads? ›

What are NPT Fittings? NPT connections seal pipes for fluid and gas transfer. They're available in iron and brass for low-pressure applications and carbon and stainless steel for higher pressure. The nominal pipe size can be identified by physically measuring the thread diameter, then subtracting 1/4″.

How far do NPT threads engaged? ›

As a general guideline, after hand-tight engagement, tighten 2-3 full turns for sizes up to 1 inches for NPT fittings. You should have between 3.5 and 6 engaged threads. Any number outside of this range may indicate either under or over tightening of the joint or out of tolerance threads.

What pressure can NPT thread hold? ›

NPT Threaded Fittings are produced to BS3799, ASTM A182 & ANSI B16. 11 as applicable. They are available in four pressure ratings: 2000lb, 3000lb, 6000lb & 9000lb.

How do NPT threads seal? ›

NPT has a tapered male and female thread which seals with Teflon tape or jointing compound. Pipe threads used in hydraulic circuits can be divided into two types: Jointing threads are pipe threads for joints made pressure tight by sealing on the threads and are taper external and parallel or taper internal threads.

Do NPT fittings need O rings? ›

Pipe fittings, which use tapered thread, don't use O-rings, but rather must use compounds or teflon tape to help seal the threads. National pipe thread taper (NPT) is a U.S. standard for tapered threads used on threaded pipes and fittings.

Why do we use NPT thread? ›

National pipe taper fuel (NPTF)

National Pipe Taper Fuel (NPTF, also called Dryseal American National Standard Taper Pipe Thread, defined by ASME B1. 20.3) is designed to provide a more leak-free seal without the use of PTFE tape (often referred to by the popular brand name "Teflon") or another sealant compound.


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