Calculators · Reference Tables

Thread Tables

Look up dimensions, pitch, threads per inch and key characteristics for six thread families. Each family has its own searchable table.

6 thread families

⚠ NPT and BSP (BSPP/BSPT) are not interchangeable — different flank angle and sealing geometry.

ISO Metric Thread

M1.6 to M300. Coarse and fine pitch. Major, minor and pitch diameters.

Unified National Coarse and Fine. Designation, TPI, pitch and basic diameters in inches and mm.

National Pipe Taper. Nominal size, TPI, OD and 1:16 taper. Incompatible with BSPT.

British Standard Pipe Parallel. Parallel form, face-seal. 55° Whitworth profile.

British Standard Pipe Taper. 1:16 taper, thread-seal. Not compatible with NPT.

29° American trapezoidal profile. Power transmission and linear motion. General and Stub ACME.