Gear Ratio Calculator
Work out the gear ratio and output speed of a pair of gears from their tooth counts and the driver speed. Enter driver gear teeth, driven gear teeth…
8 of 8 free uses remaining today
Work out the gear ratio and output speed of a pair of gears from their tooth counts and the driver speed. Enter driver gear teeth, driven gear teeth and driver speed to see gear ratio and output speed when you calculate.
Worked example
Example calculated from the starting values. Enter your own values and press Calculate to get your result.
With the default inputs (driver gear teeth = 20, driven gear teeth = 60, driver speed = 1,200 rpm), the results are: gear ratio 3.000; output speed 400.0 rpm.
Quick reference: driver gear teeth vs result
Reference table based on the example values; it is not your calculation result.
| Driver gear teeth | Gear ratio | Output speed |
|---|---|---|
| 10 | 6.000 | 200.0 rpm |
| 20 | 3.000 | 400.0 rpm |
| 40 | 1.500 | 800.0 rpm |
| 100 | 0.600 | 2,000.0 rpm |
| 200 | 0.300 | 4,000.0 rpm |
| 400 | 0.150 | 8,000.0 rpm |
Frequently asked questions
What formula does this calculator use?
Gear ratio = dn ÷ dr; Output speed = rpm × dr ÷ dn. Variables: dr = driver gear teeth, dn = driven gear teeth, rpm = driver speed in rpm.
What do I need to enter?
You need driver gear teeth, driven gear teeth, driver speed (rpm). Results update as you type.
What is an example result?
With the default inputs (driver gear teeth = 20, driven gear teeth = 60, driver speed = 1,200 rpm), the results are: gear ratio 3.000; output speed 400.0 rpm.
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