Pitch Diameter Calculator
SI
Imp
Imperial
Inputs
View results
Known pitch
Choose module, diametral pitch or circular pitch.
Module (mm)
Diametral pitch (1/in)
Circular pitch (mm)
Pitch value
(m)
Module in mm, DP in 1/in, or circular pitch in mm.
mm
Number of teeth
(z)
Gear tooth count.
Results
Default result
Edit inputs
Pitch diameter
(d)
40
mm
Also computed
Module
(m)
2
mm
Diametral pitch
(DP)
12.7
1/in
Circular pitch
(p)
6.283
mm
Addendum
2
mm
Whole depth
4.5
mm
Method notes
3 notes
Pitch diameter is the theoretical rolling circle of the gear, not the outside diameter.
For module gears, d = m·z. For diametral pitch gears, d(in) = z / DP.
Standard full-depth outside diameter is approximately d + 2m.
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