NPT vs NPTF vs BSPT vs BSPP vs Metric Threads: What Is the Difference?

Choosing the correct thread is important when selecting brass fittings, adapters, valves, and other fluid connection components. Using the wrong thread standard can result in a poor fit, leakage, damaged threads, and unexpected system downtime.

NPT, NPTF, BSPT, BSPP, and Metric threads may look identical at a glance, but they differ significantly in thread angle, profile, pitch, taper, and sealing method. This comprehensive guide explains the key differences to help you make the right choice for your piping and hydraulic systems.

NPT vs NPTF vs BSPT vs BSPP vs Metric Thread Comparison
Thread Type	NPT	NPTF	BSPT	BSPP	Metric
Description	National Pipe Taper (ANSI B1.20.1)	National Pipe Taper Fuel (ANSI B1.20.3)	British Standard Pipe Taper	British Standard Pipe Parallel	ISO Metric Thread
Thread Angle	60°	60°	55°	55°	60°
Taper/Parallel	Tapered	Tapered (Dryseal)	Tapered	Parallel	Parallel
Sealing Method	NPT threads seal through interference between the tapered threads and normally require a suitable thread sealant to help prevent leakage through the thread spiral.	Metal to metal contact. NPTF threads are designed to provide a dryseal through controlled interference between the thread crests and roots. Thread sealant may still be used depending on the application and system requirements.	BSPT threads seal through interference between the tapered threads and are commonly used with a suitable thread sealant.	BSPP threads are parallel and are generally not designed to seal on the threads. Sealing is typically achieved with an O-ring, bonded seal, gasket or other sealing element.	Metric threads are generally parallel. In fluid connections, sealing is typically achieved with an O-ring, bonded seal, gasket, sealing face, or other appropriate sealing method.
Typical Designation	1/4 NPT	1/4 NPTF	R1/4	G1/4	M12x1.5
Common Market	North America and other markets using U.S. standards	North America and selected industrial applications	Europe, Asia, Australia, New Zealand	Europe, Asia, Australia, New Zealand	Europe, Asia and other markets using ISO metric standards
Typical Application Scenarios	Industrial equipment, HVAC, plumbing, pneumatic and hydraulic systems	Fuel and oil systems, hydraulic equipment, automotive and fluid applications	Pneumatic equipment, factory automation, agricultural machinery and fluid systems	Industrial equipment, hydraulic and fluid systems, pneumatic equipment and plumbing	Automotive equipment, industrial machinery, pneumatic systems and instrumentation

4 Steps to Choose the Right Thread Before Ordering

To avoid shipping delays and incorrect assembly, always verify these four critical points with your engineering or purchasing team:

1.Thread Standard: Determine whether the mating part is NPT, NPTF, BSPT, BSPP, or Metric.

2.Thread Size and Pitch:Never identify a thread by outside diameter alone. Pipe thread sizes (NPT/BSP) are nominal and do not equal the actual measured inches. Metric threads require precise pitch measurement using a pitch gauge.

3.Gender (Male vs. Female): Confirm whether you need an external (male) or internal (female) configuration.

4.Sealing Method:Ensure you have the corresponding O-ring, bonded seal, or thread sealant required for that specific standard.

FAQ

Is NPT the same as BSP?

No. NPT and BSP are different thread standards. NPT uses a 60° thread angle, while BSP threads use a 55° Whitworth thread form. NPT and BSP should not be treated as direct equivalents.

What is the difference between BSPP and BSPT?

BSPP is a parallel thread, commonly designated as G thread. BSPT is a tapered thread, commonly designated as R for external threads. Their sealing methods are also different.

What is the difference between NPT and NPTF?

Both use a 60° tapered thread form, but NPTF is designed as a dryseal thread with controlled interference between the thread crests and roots.

Can NPT and BSPT be mixed?

They should not be considered interchangeable. Although both are tapered pipe threads, they use different thread angles and thread profiles.

NPT vs NPTF vs BSPT vs BSPP vs Metric Threads: A Guide to Brass Fittings

FAQ

Is NPT the same as BSP?

What is the difference between BSPP and BSPT?

What is the difference between NPT and NPTF?

Can NPT and BSPT be mixed?