NPT vs MPT: Which Pipe Thread Fits Your Project?
NPT stands for National Pipe Taper: a 60-degree thread that seals on the threads themselves as they tighten. MPT is simply “Male NPT,” describing the external version of that same tapered thread; the female counterpart is FPT. They are not competing standards—just gender labels for the identical taper profile.
Walk into any big-box aisle and you’ll see “MPT” stamped beside “NPT” on the same bin, making weekend plumbers think they’re two distinct threads. Suppliers use MPT/FPT to speed inventory counts, while engineers keep saying NPT for both sexes—so confusion sticks like pipe dope.
Key Differences
NPT defines the taper and pitch; MPT only tells you the fitting is male. You can mate a male NPT (MPT) with a female NPT (FPT) without adapters, but reverse the pair and nothing changes—threads still seal by interference, not by an O-ring.
Which One Should You Choose?
Use MPT when ordering a male connector—sprinkler risers, pressure gauges, hose bibbs. Specify NPT when the drawing is gender-neutral or when buying bulk threaded pipe. If you see “NPT male,” it’s the same part; just double-check the pressure class and material (brass, stainless, PVC) rather than the label.
Examples and Daily Life
Swapping a garden-hose timer? The inlet is FPT (female NPT), so grab a MPT brass nipple. Installing a reverse-osmosis faucet? The shank is MPT/NPT male; tighten into the sink deck with one wrap of PTFE tape—no pipe wrenches needed.
Can I use MPT with BSP?
No. MPT/NPT has a 60° flank angle; BSP uses 55°. They look similar but will leak or gall under pressure.
Do I need sealant on MPT threads?
Yes. Tapered threads seal by deformation; PTFE tape or pipe dope fills micro-gaps and prevents galling.
Is “MIP” the same as MPT?
Practically yes—MIP (Male Iron Pipe) is just another retailer label for male NPT threads.