🎓 Engineering • Mechanical Engineering
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Gear Ratio & Speed Reducer Calculator
Computes gear train mechanical advantage, rotational velocity step-down, and torque amplification.
Gear Ratio & Speed Reducer / Torque Multiplier
Calculates gear mechanical advantage, output rotational RPM, output torque, and center distance
Mechanical Gearbox Presets
Meshing Gears Kinetic Simulator (Pitch Circle Ratio)
Gear Ratio GR = N₂ / N₁ = 60 / 20 = 3
Output Speed = RPM₁ / GR = 1800 / 3 = 600 RPM
Output Torque = τ₁ × GR × η = 25 N·m × 3 × 95% = 71.25 N·m
Gear Ratio
3 : 1
Advantage factor: 2.85xOutput Shaft Speed
600 RPM
Reduced by 3xOutput Shaft Torque
71.25 N·m
52.6 ft·lbWhat is a Gear Ratio?
A gear ratio is the ratio of the number of teeth on the driven gear to the driving gear, determining mechanical torque multiplication and speed reduction.
Formula & Step-by-Step Calculation
GR = N_driven / N_driver, RPM_out = RPM_in / GR, τ_out = τ_in · GR · η
Gear ratio, angular velocity reduction, and multiplied torque with efficiency η.
Worked Step-by-Step Examples
Example 1
A 20-tooth pinion drives a 60-tooth gear with 1,800 RPM and 25 N·m input (95% efficiency)
Solution: Gear Ratio 3.00:1, Output Speed: 600.0 RPM, Output Torque: 71.25 N·m
• GR = 60 / 20 = 3.00; RPM_out = 1800 / 3 = 600 RPM; Torque = 25 × 3 × 0.95 = 71.25 N·m
Common Real-World & Academic Use Cases
- ✓ Automotive transmission final drive differential sizing
- ✓ Industrial robotic arm servo gearbox reduction
- ✓ Wind turbine planetary speed increaser design
How to Use the Gear Ratio & Speed Reducer Calculator
1
Enter Driver & Driven Teeth
Input N1 and N2.
2
Enter Input RPM & Torque
Input motor speed and torque.
3
Read Output Power & Speed
Inspect resulting RPM and torque.
Frequently Asked Questions
Q: What is an idler gear?
A gear inserted between the driver and driven gear that changes rotational direction without altering the overall gear ratio.