Are you confused about which faucet thread size to choose for your kitchen, sink, bathroom, or outdoor faucet?
The thread size of a faucet is a critical factor, as it directly affects the compatibility of the faucet with your plumbing system.
Here, we’ll provide the standard faucet thread sizes for different types of faucets and tips on measuring your faucet’s thread size.
Keep reading, and let’s learn more about it in the following sections.
Standard Kitchen Faucet Thread Size
Because there are so many kitchen faucets available in the market, no standard thread size is dedicated to the kitchen.
But, the thread size may vary depending on the thickness of the faucet hole. This hole determines the amount of water from 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 faucet thread size.
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 bathroom faucet 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 Female Hose Threads are also called FHT. Moreover, NHR is used for thin-walled couplers, whereas NH is used for female hose ends.
The standard garden hose thread size is 27 mm or 1 1/16 inches of 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 1-inch or ⅞ inches BSP outlet is used for horticulture, farm, factory, and garden irrigation taps.
How to Determine Any Faucet Thread Size?
Step 1: 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.
Step 2: 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?
No. All the faucet threads are not the same.
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.
For example, a ½ inch of 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 tiny, you must use a thread gauge or a chart to measure the TPI.
Straight vs. Tapered Threads
National Pipe Straight (NPS) is the common name for North American threads. However, if you live outside North America, the standard is BSP.
The good news is that both NPS and BSP have the same shape, pitch, and angle. However, the NPS threads are straight, whereas the BSPs 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 seals properly on their own, you will need a plumber’s tape to finalize the fitting.
Common Threads in the Market
| Abbreviation | Detail | Compatibility with Most Supply Connections |
| NPS | National Pipe Straight National Pipe Standard | Yes |
| NPT | National Pipe Thread National Pipe Tapered National Pipe Thread (Tapered) | Yes No No |
| IPS | International Pipe Size International Pipe Standard Iron* Pipe Size Iron* Pipe Standard | Yes Yes Yes Yes |
| FIP | Female Iron* Pipe Female International Pipe | Yes Yes |
| MIP | Male Iron* Pipe Male International Pipe | Yes Yes |
| FPT | Female Pipe Thread Female Pipe Tapered Female Pipe Thread (Tapered) | Yes No No |
| MPT | Male Pipe Thread Male Pipe Tapered Male Pipe Thread (Tapered) | Yes No No |
| GHT | Garden Hose Thread | No |
| BSP | British Standard Pipe | No |
To Conclude
Now, do you have the answer to your questions about the standard thread sizes for different faucets in the household?
As you see, indoor faucets have no specific ideal thread sizes. But, for outdoor faucets, for example, garden hoses, there are standard sizes assigned to every country.
I have discussed what’s recommended for outdoor faucet threads in Britain and North America. You must check for yourself the ideal thread size recommended in your country.
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.
James is an organic fertilizer professional who owns a successful organic fertilizer company in new jersey. He is an expert in waste management in both houses and community cases. In his free time, he loves to write about his experiences in the field.