Gear Ratio Calculator
Calculate gear ratio, output RPM, and torque multiplication from input/output teeth count.
Gear Train Parameters
Ratio = Nout / Nin | RPMout = RPMin / Ratio | Tout = Tin × Ratio × η
Results
Gear Ratio
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Output RPM
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Output Torque
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Input Power
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Output Power
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Type
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How this was calculated
Gear ratio: Driven teeth / Driving teeth. A ratio > 1 is a speed reducer (torque multiplier). Ratio < 1 is a speed increaser.
Power: HP = Torque(ft-lb) x RPM / 5252. Output power = Input power x efficiency.
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Book a free strategy call →Understanding Gear Ratios
A gear ratio describes the relationship between the rotational speeds of two meshing gears. When a small driving gear meshes with a larger driven gear, speed decreases but torque increases proportionally (minus friction losses). This principle is fundamental to transmissions, pumping units, compressors, and industrial machinery.
Typical mesh efficiencies are 95-98% for spur gears, 90-95% for worm gears. Compound gear trains multiply individual stage ratios for higher overall reduction.
Built by Groundwork Analytics.