Mechanical design reference

Gear Pitch Conversion Table

Convert between diametral pitch, circular pitch, and metric module for spur gear selection, gear drawing checks, and mixed-unit mechanical design.

Design reference

Search gear pitch conversion table

Use the searchable table to filter the reference data by the values, symbols, sizes, and applications that matter for your design check.

Gear Pitch

Quick check

Table search

Filter the table by size, symbol, process, value, or application without scanning the whole chart.

Quick check

Design check

Use the table for early sizing and drawing checks, then confirm final values against the governing standard.

Reference table

Gear pitch conversion chart

Diametral Pitch (DP)	Circular Pitch (CP, mm)	Module (m, mm)
8	9.927	3.175
10	7.958	2.54
12	6.632	2.117
16	4.964	1.587
20	3.979	1.27
24	3.316	1.058
32	2.482	0.794
40	1.990	0.635
48	1.658	0.529

How to use

Practical checks for gear pitch conversion table

Unit conversion

mm = in × 25.4

Use this for inch-to-metric conversions where the page includes dimensional data.

Clearance check

clearance = hole size - feature size

Positive clearance helps confirm whether a part can assemble freely.

Tolerance range

range = upper limit - lower limit

The usable manufacturing window is the difference between upper and lower limits.

Documentation check

value + unit + standard

Reference data is most useful when paired with units and the governing drawing or design standard.

Definitions

What the reference values mean

Reference Value

A tabulated value used for selection, comparison, or early design checks.

Nominal Size

The named or target size before manufacturing tolerance is applied.

Tolerance

The allowed variation from the nominal or specified value.

Standard

The source convention or governing document that defines how a value should be interpreted.

FAQ