When to use this calculator
Estimate standard centre distance for two external gears of the same module. Standard external spur gears without profile-shift centre-distance correction.
Explore the gears, belts & motion calculators for other questions in this topic. For a related calculation, use the Gear Output Speed Calculator: Find output rotational speed from an input speed and two gear tooth counts.
PUTTING IT INTO PRACTICE
Gear Centre Distance: 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 |
|---|---|
| Common module (mm) | 2 |
| First teeth (integer) | 20 |
| Second teeth (integer) | 40 |
| Result | 60 mm |
- Check the input labels and enter the example values above.
- Apply the relationship: Standard centre distance = module × (teeth one+teeth two)/2.
- The result is 60 mm, rounded for display.
How to interpret your result
Standard external spur gears without profile-shift centre-distance correction.
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 centre distance calculator useful?
Estimate standard centre distance for two external gears of the same module. Standard external spur gears without profile-shift centre-distance correction.
How do I use the gear centre distance calculator?
Enter common module (mm), first teeth (integer), second 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?
Standard centre distance = module × (teeth one+teeth two)/2.
What should I check before using the result?
Standard external spur gears without profile-shift centre-distance correction.
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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