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MJ
Md Jony Islam
Last updated: Jun 14, 2026

Gear Ratio Calculator

Calculate gear ratios, speed ratios, and mechanical advantage for spur, helical, and bevel gears. Step-by-step solutions for engineering and mechanical design.

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Driving (Input) Gear

Driven (Output) Gear

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Gear Ratio Calculator

Calculate gear ratios, speed ratios, and mechanical advantage for spur, helical, and bevel gears. Step-by-step solutions for engineering and mechanical design.

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Gear Ratio calculator:

This Gear Ratio Calculator uses gear ratio, speed of the rotating machine, and torque of the rotating machine. Use the number of teeth, or enter the speed, to use step-by-step solutions to compute gear performance.

Mechanical Gear Ratio Tools formula

The Gear Ratio Calculator assists engineers, students, and technicians in calculating gear ratios, speed ratios, and mechanical advantages in gears. Gear ratio: The gear ratio is the ratio of the teeth of the driven gear to those of the driving gear:

The user can key the number of teeth on the driver and driven gears, key speed, or key mechanical advantage. The The calculator takes the gear ratio, output speed,d, and torque, and gives step-by-step solutions to the spur gear system. helical gear system, bevel gear system, and finally, the compound gear system.

\[ \textrm{Gear Ratio} = \frac{N_{driven}}{N_{driver}} \]

Gear teeth, speed, and torque are shown to interact step-by-step, and it is straightforward to design gearboxes, mechanical transmissions, and automotive gear systems. SI units are welcomed: RPM speed, N.m. torque. The tool is best suited to mechanical engineers, automotive designers, and students, and can be used to analyze and design mechanical gear systems with the correct accuracy.

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Work & Installation — Input to Output Summary

Input:

  • Number of teeth of driver gear (N_driver)
  • Number of teeth of driven gear (N_driven)
  • Optional: input speed (RPM)
  • Optional: input torque (NĀ·m)

Processing:

  • Compute gear ratio: GR = N_driven / N_driver
  • Compute output speed: RPM_out = RPM_in / GR
  • Compute output torque: T_out = T_in Ɨ GR
  • Validate input values and units

Output:

  • Gear ratio (GR)
  • Output speed (RPM_out)
  • Output torque (T_out)
  • Step-by-step formulas and calculations

Testing and Final Adjustments

Test examples:

  • Spur gear: N_driver = 20, N_driven = 60 → GR = 3, speed reduced by 3Ɨ, torque multiplied by 3
  • Helical gear: N_driver = 15, N_driven = 45 → GR = 3, RPM_out = RPM_in / 3
  • Compound gear train: calculate overall ratio by multiplying individual ratios
  • Edge cases: N_driver = 0 → error; N_driven = 0 → GR = 0
  • Units validation: RPM, NĀ·m
  • Step-by-step clarity for students and engineers
  • Mobile/desktop UX: numeric keypad, labels, dropdown for gear type
  • Include examples: automotive gearbox, industrial gear trains, speed reducers, torque multipliers
  • SEO metadata: "Gear Ratio Calculator," "Spur & Helical Gear Tool," "Mechanical Advantage Calculator," schema markup
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Frequently Asked Questions - Gear Ratio Calculator:

Gear ratio is the ratio of the number of teeth of the driven gear to the driving gear.
Gear Ratio = N_driven / N_driver, where N represents the number of teeth.
RPM_out = RPM_in / Gear Ratio.
T_out = T_in Ɨ Gear Ratio.
Yes, this calculator supports all common gear types.
Mechanical engineers, automotive designers, and students analyzing gear systems.
Yes, all formulas and intermediate steps are displayed for clarity.
It produces an error; driver teeth must be greater than zero.
Yes, multiply individual gear ratios to find overall ratio.
It determines the speed and torque relationship between input and output shafts in a mechanical system.
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