Gear Pitch Conversion
Convert gear pitches between Diametral Pitch (DP), Circular Pitch (CP), and Module (m) for standard gear design
Gear Pitch Conversion Table
| 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 |
About Gear Pitch Conversion
This detailed gear pitch conversion guide provides engineers, machinists, and designers with accurate relationships between Diametral Pitch (DP), Circular Pitch (CP), and Module (m). Understanding these conversions is essential for ensuring proper gear meshing, consistent performance, and international design compatibility in mechanical and manufacturing applications.
The conversion table allows quick comparison of imperial and metric pitch standards used in gear design, power transmission, and mechanical prototyping. Whether working with inch-based Diametral Pitch or metric Module systems, accurate conversion ensures gears operate efficiently and conform to design intent across global standards.
Gear Pitch Terminology and Formulas
-
Diametral Pitch (DP) – Represents the number of teeth per inch of the pitch diameter. Used primarily in imperial gear systems.
Formula:DP = Number of Teeth / Pitch Diameter (in) -
Circular Pitch (CP) – The distance between identical points on adjacent teeth measured
along the pitch circle. This value directly affects tooth spacing and smooth engagement.
Formula:CP = π / DP (in)orCP = π × m (mm) -
Module (m) – The metric equivalent of pitch diameter per tooth. Standardized globally under ISO gear design practices.
Formula:m = Pitch Diameter / Number of Teeth (mm)
Applications in Mechanical Design and Manufacturing
Converting between DP, CP, and Module is critical for:
- Ensuring interchangeability between imperial and metric gear systems.
- Verifying accurate tooth geometry in CAD modeling and CAM programming.
- Supporting precision manufacturing of gears, pinions, and mating components.
- Facilitating gear selection and ratio calculation in design optimization.
This gear pitch conversion table simplifies the design process, helping professionals avoid dimensional errors, ensure smooth transmission, and maintain reliability in mechanical assemblies. It is a vital reference for gear design engineers, mechanical drafters, and production specialists working across both imperial and metric systems.