Thread Table

Use our thread table to look up the pitch and threads-per-inch for the most common screw sizes.
PITCH (MM)
THREADS PER INCH (TPI)
Size Coarse Fine Extra Fine UNC UNF BSW BSF
M1.6 - #0 0.35 - - - 80 - -
M2 - #1 0.4 - - - 72 - -
- - #2 - - - 56 64 - -
M2.5 - #3 0.45 - - 48 56 - -
- - #4 - - - 40 48 - -
M3 1/8" #5 0.5 - - 40 44 40 -
M3.5 - #6 0.6 - - 32 40 - -
M4 - #8 0.7 - - 32 36 - -
M5 3/16" #10 0.8 - - 24 32 24 32
- - #12 - - - 24 28 - -
M6 1/4" - 1 - - 20 28 20 26
M8 5/16" - 1.25 1 - 18 24 18 22
M10 3/8" - 1.5 1.25 1 16 24 16 20
- 7/16" - - - - 14 20 14 18
M12 1/2" - 1.75 1.5 1.25 13 20 12 16
M14 9/16" - 2 1.5 - 12 18 12 16
M16 5/8" - 2 1.5 - 11 18 11 14
M18 - - 2.5 1.5 - - - - -
M20 3/4" - 2.5 1.5 - 10 16 10 12
M22 7/8" - 2.5 1.5 - 9 14 9 11
M24 1" - 3 2 - 8 12 (14) 8 10

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