⚙️ Gear Ratio Calculator
Ratio, output RPM and torque from tooth counts — live.
Driving gear teeth
Driven gear teeth
Input RPM
Input torque (optional)
N·m
ft·lb
Efficiency per mesh (%)
Spur gears ≈ 97%
Tire diameter (in, optional)
For road speed
Results
ratio = driven ÷ driver · output RPM = input RPM ÷ ratio · output torque = input torque × ratio × efficiency
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Gear Ratio Calculator