MachineCalcs

Finder

Thread Identifier

Enter a measured outside diameter and pitch or TPI. The finder ranks common metric, UNC and UNF threads by closeness, then shows the likely designation and a 75% tap drill reference. Use thread wires or gauges for production inspection.

Measure the outside diameter across thread crests. For pitch, use a thread gauge or count threads over a measured length. Worn parts can land between standards.

Closest matches

Live match

M2

Metric coarse

#1
Major
2 mm
Pitch
0.4 mm
TPI
63.5

M2x0.25

Metric fine

#2
Major
2 mm
Pitch
0.25 mm
TPI
101.6

M2.5

Metric coarse

#3
Major
2.5 mm
Pitch
0.45 mm
TPI
56.44

M2.5x0.35

Metric fine

#4
Major
2.5 mm
Pitch
0.35 mm
TPI
72.57

M3

Metric coarse

#5
Major
3 mm
Pitch
0.5 mm
TPI
50.8

M3x0.35

Metric fine

#6
Major
3 mm
Pitch
0.35 mm
TPI
72.57

M4

Metric coarse

#7
Major
4 mm
Pitch
0.7 mm
TPI
36.29

M4x0.5

Metric fine

#8
Major
4 mm
Pitch
0.5 mm
TPI
50.8

How to use the match

The ranked result is a dimensional clue, not an inspection report. After finding a likely thread, confirm flank angle, class of fit, handedness and actual pitch diameter before ordering tooling or releasing a drawing. For drill sizing, use the tap drill calculator.