Gear Parameter Calculator

Standard spur gear parameter calculator. Supports forward design and reverse-engineering from measured OD.

Core Formulas: d = m·z  |  da = m(z+2)  |  df = m(z−2.5)  |  a = m(z₁+z₂)/2
teeth
mm
Standard:
teeth

Gear 1 Parameters

Circular Pitch p = πm
- mm
Addendum ha = m
- mm
Dedendum hf = 1.25m
- mm
Whole Depth h = 2.25m
- mm
Pitch Circle Dia. d = m·z
- mm
Tip Diameter da = m(z+2)
- mm
Root Diameter df = m(z−2.5)
- mm

Reference

Gear Formulas

ParameterSymbolFormula
Circular Pitchpπ·m
Addendumham
Dedendumhf1.25m
Whole Depthh2.25m
Pitch Circledm·z
Tip Diameterdam(z+2)
Root Diameterdfm(z−2.5)
Center Distanceam(z₁+z₂)/2

Reverse Engineering Method

  1. Count the teeth (Z)
  2. Measure the outer diameter (Da)
  3. Calculate module: M = Da / (Z+2)
  4. Round to nearest standard module

Standard modules: 0.1, 0.12, 0.15, 0.2, 0.25, 0.3, 0.4, 0.5, 0.6, 0.75, 0.8, 1, 1.25, 1.5, 2, 2.5, 3, 4, 5, 6, 8, 10