Chains & Sprockets
Sprocket Ratio Calculator
Enter the tooth counts of the driver and driven sprockets to calculate the ideal chain-drive ratio.
Inputs
Formula
Sprocket speed ratio
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
- Driver sprocket teeth
- 20 teeth
- Driven sprocket teeth
- 60 teeth
Result
- Speed reduction ratio
- 3 :1
Related calculators
Continue your workflow with a related calculation.
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Sprocket RPM Calculator
Calculate driven sprocket RPM from driver RPM and sprocket tooth counts.
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Sprocket Teeth Calculator
Estimate the driven sprocket tooth count needed for a target RPM.
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Sprocket Torque Ratio Calculator
Estimate ideal driven-shaft torque from input torque and driver/driven sprocket tooth counts.
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Chain Speed Calculator
Calculate roller-chain linear speed from chain pitch, sprocket teeth, and RPM.
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Chain Length Calculator
Estimate roller-chain length in pitches from sprocket teeth, center distance, and chain pitch.
Frequently asked questions
What does a 3:1 sprocket ratio mean?
Ideally, the driven shaft turns once for every three revolutions of the driver.
Does chain pitch affect the speed ratio?
No. For two matching chain sprockets, the ideal speed ratio is set by tooth counts.