3/4 GHT ≠ G3/4 BSPP

Will this garden tap and hose fitting connect?

Two parts can both say “3/4 inch” and still use different threads. Enter the markings on both threaded ends. This check gives the mating thread and male/female wording for an adapter, or stops when the evidence is too weak.

Quick answer: 3/4 GHT is about 27.0 mm outside diameter and 11.5 threads per inch; a parallel G3/4 BSPP thread is about 26.4–26.5 mm and 14 TPI. Diameter alone is not a safe identifier. Do not force a fitting.

One job · no account

Check the two ends

Tap / first part Printed thread marking Threaded end

Male outside diameter, mm (optional)Threads per inch (optional)

Hose / second part Printed thread marking Threaded end

Male outside diameter, mm (optional)Threads per inch (optional)

Choose BSPP only when the part or manufacturer confirms a parallel G thread. A bare “BSP” label does not establish that. Measure only an accessible male thread. A hose's inner diameter is not its thread size. Quick-connect fittings and tapered pipe threads are outside this check.

What the markings mean

3/4 GHT / NH

North American garden hose thread: straight, about 1.062 in (27.0 mm) male outside diameter, 11.5 TPI. The actual fitting and washer must be checked.

G3/4 BSPP

Parallel British Standard Pipe thread: approximately 26.4–26.5 mm male outside diameter and 14 TPI. “3/4” is a nominal designation, not the outside diameter. BSPT/R is tapered and outside this check.

Near-matching outside diameters are not proof of the same thread. A 14-TPI measurement near 26.5 mm cannot by itself distinguish parallel G/BSPP from tapered or other pipe-thread forms. Use the exact part marking or manufacturer documentation before buying an adapter.

Sources and limits

Task Force Tips thread chart — 3/4-11.5 NH/GHT outside diameter and pitch.
Hozelock tap connector — 3/4 BSP garden tap dimensions.
Parker thread identification guide — BSP outside diameter and 14-TPI table.
Parker parallel/taper thread guide — G denotes parallel BSPP; R denotes tapered BSPT.

This is a label-matching aid, not a certification of pressure rating, seal design, leak resistance or product compatibility. It does not identify unmarked threads conclusively.