Gears
Gear Pitch Diameter Calculator
Enter metric module and tooth count to calculate the standard spur gear reference or pitch diameter.
Inputs
Formula
Standard spur gear reference diameter
Worked example
Using the default values shown in the calculator, the same formula gives the following result. This is a quick sanity check for the calculation, not a design recommendation.
Inputs
- Module
- 2 mm
- Number of teeth
- 30 teeth
Result
- Reference diameter
- 60 mm
Related calculators
Continue your workflow with a related calculation.
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Calculate tip or outside diameter for a standard full-depth external metric spur gear.
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Calculate center distance for two standard external spur gears from module and tooth counts.
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Gear Circular Pitch Calculator
Calculate circular pitch for a metric gear from module using the standard pi-times-module relationship.
Technical references for this calculation
Frequently asked questions
Is reference diameter the same as outside diameter?
No. For a standard external spur gear, outside diameter is larger than the reference diameter by two addenda.
What gear type does this formula assume?
It assumes a standard metric spur-gear reference geometry where reference diameter equals module times tooth count.