Gear Module & Pitch
Compute pitch diameter D, addendum da, root df, circular pitch t and centre distance C from module m and teeth Z; also diametral pitch Pd.
Inputs
Formula
D = mZ; da = m(Z+2); df = m(Z-2.5); t = πm; C = m(Z1+Z2)/2; Pd = 25.4/m
How to use
- Fill in Module m, Teeth Z, Mate teeth Z₂ in the Inputs section (watch the unit on each field).
- Click Calculate; the tool evaluates the formula shown above.
- Read Pitch diameter, Addendum dia., Root dia., Circular pitch, Centre distance, Diametral pitch in the results area.
Formula notesModule m = d / z (pitch diameter / tooth count); tooth height h ≈ 2.25 m.