Hose Bib Thread Size: Standard Sizes and How to Measure

Hose bib thread size is easy to confuse because two different standards meet at the same outdoor faucet. The pipe side usually uses tapered pipe threads such as NPT, while the hose side uses Garden Hose Thread, or GHT. Getting the measurement right before you buy an adapter, backflow preventer, or replacement spigot saves a trip back to the hardware store.

Standard Hose Bib Thread Sizes

• 3/4 inch GHT: The most common size for residential hose connections. A standard garden hose attaches directly to a 3/4-inch GHT male or female fitting.
• 1/2 inch NPT: Frequently used where the spigot connects to the supply pipe inside the wall. This is a tapered pipe thread, not a hose thread.
• 3/4 inch NPT: Sometimes found on larger commercial or irrigation hose bibs where higher flow is needed.
• 1/2 inch GHT: Less common, but appears on some specialty hoses, sprayers, and portable equipment.

The key point is that GHT and NPT are not interchangeable. GHT is a straight thread designed to seal with a washer, while NPT is tapered and seals by tightening the threads themselves.

How to Measure a Hose Bib Thread

1. Measure the outside diameter of the male thread with calipers or a ruler.
2. Count the threads in one inch with a thread gauge if you have one.
3. Compare your measurement to the common sizes above. A standard garden hose thread is roughly 1-1/16 inches outside diameter and about 11.5 threads per inch.
4. If the fitting is inside the wall or attached to pipe, check whether the threads taper. Tapered threads usually point to NPT rather than GHT.

If you are still unsure, bring the old fitting to the store and match it against a known adapter.

Hose Bib vs. Spigot vs. Sillcock

These terms are often used interchangeably. A hose bib is the outdoor faucet with a threaded outlet for a hose. A spigot is any faucet with a hose connection. A sillcock is a hose bib that extends through an exterior wall and usually has a longer body and anti-siphon protection. For thread sizing, the same GHT and NPT rules apply to all three.

See our full explanation of hose bib vs. spigot if you are choosing between replacement terms or products.

Frequently Asked Questions

Is a hose bib 3/4 inch or 1/2 inch?

The hose connection is normally 3/4-inch GHT, while the pipe connection into the wall is often 1/2-inch NPT. Check both ends because they frequently use different standards.

Can I connect a 3/4 hose to a 1/2 bib?

No, not directly. Use a reducing adapter that matches both thread standards on each side.

How do I know if I have GHT or NPT?

GHT fittings use a flat washer at the end and the threads are straight. NPT threads taper and seal by interference between the threads. A garden hose fitting is almost always GHT.

For related thread guides, see how to determine NPT thread size and MIP vs. NPT thread.