When to use this calculator
Find nominal pitch diameter from gear module and tooth count. Applies to metric module gearing under its pitch-circle definition.
Explore the gears, belts & motion calculators for other questions in this topic. For a related calculation, use the Gear Ratio Calculator: Find the tooth-count ratio of a simple gear pair.
PUTTING IT INTO PRACTICE
Gear Pitch Diameter: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| Gear module (mm) | 2 |
| Teeth (integer) | 30 |
| Result | 60 mm |
- Check the input labels and enter the example values above.
- Apply the relationship: Pitch diameter = module × tooth count.
- The result is 60 mm, rounded for display.
How to interpret your result
Applies to metric module gearing under its pitch-circle definition.
Use compatible modules and effective pitch dimensions. No-slip and ideal-mesh assumptions omit losses and dynamics. A ratio calculation does not select a safe shaft, belt, bearing or gear rating.
Frequently asked questions
Why is a lead-screw lead different from its pitch?
Pitch is the axial distance between thread forms. A multi-start screw advances by pitch times the number of starts per revolution.
When is the gear pitch diameter calculator useful?
Find nominal pitch diameter from gear module and tooth count. Applies to metric module gearing under its pitch-circle definition.
How do I use the gear pitch diameter calculator?
Enter gear module (mm), teeth (integer). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Pitch diameter = module × tooth count.
What should I check before using the result?
Applies to metric module gearing under its pitch-circle definition.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
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