How to Measure Garden Hose Fitting Size | Threads & Diameter

Measure a garden hose fitting by checking the threaded coupling’s diameter and threads per inch, not the hose tube itself — the standard US fitting is 3/4-inch GHT with 11.5 TPI.

A leaking hose connection or a new nozzle that doesn’t fit means one thing: the fitting size is wrong. The fix is simple once you know that the fitting size and the hose diameter are two separate numbers. The threaded metal coupling at each end follows a single standard across nearly all US residential hoses, but verifying it takes about two minutes with the right tool.

What Size Are Standard Garden Hose Fittings?

Every standard residential garden hose sold in the United States and Canada uses a 3/4-inch GHT (Garden Hose Thread) fitting, regardless of the hose’s internal diameter. The male coupling has an outer diameter of roughly 1.06 inches and a thread pitch of 11.5 threads per inch. This is a straight, non-tapered thread that seals against a rubber washer — not a tapered pipe thread like NPT.

How To Measure Your Fitting Step By Step

Measuring a garden hose fitting size correctly means focusing on the metal coupling, not the hose tube. Follow these four steps with a caliper or a ruler.

Step 1: Disconnect Everything. Remove the hose from the spigot and detach any sprayer, nozzle, or splitter so you’re measuring bare threads.

Step 2: Measure the Coupling Diameter. For a male fitting (threads on the outside), measure the outer diameter across the widest part of the threads using a vernier caliper. For a female fitting (threads on the inside), measure the inner diameter. A standard 3/4-inch GHT male coupling will read roughly 1.0625 inches (about 27 mm).

Step 3: Count the Threads Per Inch. Place a thread gauge or a ruler against the threaded section and count how many thread peaks fall within one inch. The US standard is 11.5 TPI — if you count roughly 11 to 12 threads in an inch, you have a standard GHT fitting.

Step 4: Confirm With the Spec. If your male fitting has an OD of about 1.06 inches and 11.5 TPI, the fitting is 3/4-inch GHT. If you’re buying adapters — like a 45-degree water hose elbow for tight spigot spaces — look for “3/4-inch GHT” on the package.

Hose Diameter vs. Fitting Size: The Common Confusion

Hose diameter — usually 1/2 inch, 5/8 inch, or 3/4 inch — refers to the inner opening that carries water, not the threaded connection. You can swap a 5/8-inch hose for a 3/4-inch hose and use the same fittings because the coupling size stays the same. The diameter affects flow rate: For most homeowners, a 5/8-inch by 50-foot hose is the sweet spot between flow and easy handling.

What To Avoid When Measuring Or Connecting

Three mistakes cause most fitting headaches. First, never assume a tapered pipe thread (NPT) will seal against a straight garden thread — the taper lets air and water past. Use a 3/4-inch GHT to 1/2-inch NPT adapter if connecting to a plumbing pipe. Second, don’t measure the hose tube itself and call that the fitting size; the tube and the coupling are always different numbers. Third, tighten the coupling only a quarter to half turn after the washer makes contact — over-tightening crushes the washer and causes drips.