What is the Standard Kitchen, Sink, Bathroom, Outdoor Faucet Thread Size?

Are you confused about the size of your faucet thread? 

You can find various types of faucets for different parts of the house. Usually, we need a faucet in the kitchen, bathroom, and in the garden. Do you think they all use the same size of faucet thread?

The answer is no. Sizes of the faucet thread may vary depending on the size and style of the faucet in the household.

Let’s get to know more about it in the following sections. 

Standard Kitchen Faucet Thread Size

Because there are so many types of kitchen faucets available in the market, there is no standard thread size dedicated to the kitchen. But the size of the thread may vary depending on the thickness of the faucet hole.

This hole determines the amount of water that will come out of the faucet at a given time. The ideal hole size of the kitchen sink is 34.925 millimeters or 1⅜ inches.  

Standard Sink Faucet Thread Size

The answer to the standard size of the sink faucet is pretty much the same as the kitchen and bathroom faucets. Threads usually differ based on the style and size of the faucet in question. So, it’s hard to tell the exact ideal size of the faucet thread. 

Standard Bathroom Faucet Thread Size

Bathroom faucets are the same as kitchen sink faucets. The size of the thread depends on the size of the faucet hole. There are no strict standards, but the most common thread sizes are 15/16 inches male and 55/64 inches female. 

If your bathroom faucet has protruding threads, then your sink is male. You need to get a female threaded aerator to attach to it. On the other hand, if your bathroom faucet’s thread is located inwards, it’s a female faucet. So you need a male threaded aerator. 

Standard Outdoor Faucet Thread Size

Outdoor faucet threads are different from indoor faucet threads. The standard outdoor faucet threads in the United States, Canada, and surrounding territories use Garden Hose Thread (GHT). It’s also sometimes called National Thread (NT). 

Male Hose Threads are abbreviated as MHT and the Female Hose Threads are also called FHT. More on this, NHR is used for thin-walled couplers, whereas the NH is used for female hose ends. 

The standard garden hose thread size is 27 mm or 1 1/16 inches non-tapered diameter straight thread with a pitch of 11.5 threads per inch.

For hoses with an inner diameter of ½ inch, ¾ inch, and ⅝ inches, the experts recommend a ¾ inch GHT for the best fit. 

On the other hand, outdoor faucet threads are known as British Standard Pipe (BSP). A BSP outlet of 1 inch or ⅞ inches is used for horticulture, farm, factory, and garden irrigation taps. 

How to Determine Any Faucet Thread Size?

To determine the actual size of your faucet thread, first, unscrew the faucet aerator. Taps with threads located outside are male threads. The threads that are located inside are female threads. 

Once you have the thread, measure it with a measuring tape or ruler. They should be around 1 inch or so. 

Are All Faucet Threads the Same?

A tap aerator can be divided into different categories based on the type of stream and flow rate. They are also classified based on gender- male or female.

In the United States of America, a standard male thread is 15/16″-27 and a standard female thread is 55/64″-27. The size may vary if you live elsewhere. If so, get in touch with a local expert for advice. 

Is the Thread Size the Same as the Diameter of the Thread?

Not at all. The thread size is not the same as the diameter of the thread. As an example, a ½ inch BSP thread may have a diameter of 53/64 inches or 21 mm. 

What is Thread Pitch or Threads Per Inch?

Thread pitch or the threads per inch (TPI) means the number of peaks and valleys on the thread. You have to look at the thread closely to see the TPI. The taper rate of NPT threads is 1 in 16 inches, its roots and crests are flat, and it has a 60-degree thread angle. 

Since it’s so small, to measure the TPI, you have to use a thread gauge or a chart. 

Straight vs. Tapered Threads

National Pipe Straight (NPS) is the standard name for North American threads. However, if you live outside North America, the standard is known as BSP. 

The good news is that both NPS and BSP have the same shape, pitch, and angle. But, the NPS threads are straight, whereas the BSP are tapered.

Generally, straight pipe threads are used on showerheads, faucets, fittings, and hoses. Meanwhile, the tapered ones are found on couplings, tees, elbows, nipples, and pipe ends. Also, since none of them seal properly on their own, you will need a plumber’s tape to finalize the fitting. 

Common Threads in the Market

AbbreviationDetailCompatibility with Most Supply Connections 
NPSNational Pipe Straight
National Pipe Standard
Yes
NPTNational Pipe Thread
National Pipe Tapered
National Pipe Thread (Tapered)
Yes
No
No
IPSInternational Pipe Size
International Pipe Standard
Iron* Pipe Size
Iron* Pipe Standard
Yes
Yes
Yes
Yes
FIPFemale Iron* Pipe
Female International Pipe
Yes
Yes
MIPMale Iron* Pipe
Male International Pipe
Yes
Yes
FPTFemale Pipe Thread
Female Pipe Tapered
Female Pipe Thread (Tapered)
Yes
No
No
MPTMale Pipe Thread
Male Pipe Tapered
Male Pipe Thread (Tapered)
Yes
No
No
GHTGarden Hose ThreadNo
BSPBritish Standard PipeNo

[Collected from https://ambassadorfaucets.com/supply_fitting_connections]

To Conclude

Now, do you have the answer to your questions about the standard sizes of threads for different faucets in the household?

As you see, there are no specific ideal thread sizes for indoor faucets. But, when it comes to outdoor faucets, for example, garden hose, there are standard sizes assigned to every country. 

I have talked about what’s recommended in Britain and North America for outdoor faucet threads. You have to check for yourself the ideal thread size recommended in your specific country. 

In all, you don’t need to worry much about getting the right faucet thread for your indoor faucets. Just measure the diameter of your household faucet, and then go to the hardware store to get the ideal thread for that.