When to use this calculator
Find output rotational speed from an input speed and two gear tooth counts. Direction reverses for one external mesh; this scalar result reports speed magnitude only.
Explore the gears, belts & motion calculators for other questions in this topic. For a related calculation, use the Gear Pitch Diameter Calculator: Find nominal pitch diameter from gear module and tooth count.
PUTTING IT INTO PRACTICE
Gear Output Speed: 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 |
|---|---|
| Input speed (rpm) | 1,200 |
| Driving teeth (integer) | 20 |
| Driven teeth (integer) | 60 |
| Result | 400 rpm |
- Check the input labels and enter the example values above.
- Apply the relationship: Output speed magnitude = input rpm × driving teeth/driven teeth.
- The result is 400 rpm, rounded for display.
How to interpret your result
Direction reverses for one external mesh; this scalar result reports speed magnitude only.
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 output speed calculator useful?
Find output rotational speed from an input speed and two gear tooth counts. Direction reverses for one external mesh; this scalar result reports speed magnitude only.
How do I use the gear output speed calculator?
Enter input speed (rpm), driving teeth (integer), driven 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?
Output speed magnitude = input rpm × driving teeth/driven teeth.
What should I check before using the result?
Direction reverses for one external mesh; this scalar result reports speed magnitude only.
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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