Gear Ratio Calculator

Calculate gear ratios, torque multiplication, speed relationships, and mechanical advantage

Simple Gears

Compound Gears

RPM Calculator

Torque Calculator

Simple Gear Ratio Calculator

Driver Gear Teeth

Driven Gear Teeth

Gear Visualization

Driver

Driven

Input RPM (Optional)

Input Torque (Optional)

N·m

ft·lb

kgf·m

Gear Ratio Results

Gear Ratio: 2.00:1

Ratio = Driven Teeth ÷ Driver Teeth = 40 ÷ 20 = 2.00:1

Speed Increase Torque Increase

Output Calculations:

Output RPM: 500 RPM
Output Torque: 200 N·m
Mechanical Advantage: 2.00
Efficiency (estimated): 98%

Speed vs Torque Relationship

Mechanical Advantage

Practical Applications

A 2:1 gear ratio means the driven gear rotates half as fast as the driver gear but with twice the torque. This is useful for applications requiring more torque at lower speeds, such as vehicle transmissions or industrial machinery.

⚙️ Understanding Gear Ratios

Gear ratios are fundamental to mechanical systems, determining the relationship between rotational speed and torque. They describe how many turns of the input gear are needed to produce one turn of the output gear.

📊 Key Gear Ratio Concepts

Fundamental principles of gear systems:

Gear Ratio: Ratio of teeth on driven gear to teeth on driver gear
Mechanical Advantage: Factor by which torque is multiplied
Speed Reduction: Inverse relationship between speed and torque
Efficiency: Percentage of power transmitted through the system

🔧 Gear Types and Applications

Different gear configurations serve various purposes:

Spur Gears: Most common, teeth parallel to axis, efficient but noisy
Helical Gears: Angled teeth, smoother and quieter operation
Bevel Gears: Transmit power between intersecting axes
Worm Gears: High reduction ratios, self-locking capability
Planetary Gears: Compact, high power density, used in transmissions

Frequently Asked Questions

What is a gear ratio? A gear ratio is the ratio of the number of teeth on two meshing gears. It determines the mechanical advantage and speed relationship between the input and output.

How does gear ratio affect torque and speed? Higher gear ratios increase torque but decrease speed, while lower ratios increase speed but decrease torque.

What's the difference between reduction and overdrive gears? Reduction gears (ratio > 1:1) increase torque and reduce speed. Overdrive gears (ratio < 1:1) increase speed and reduce torque.

How do I calculate output RPM? Output RPM = Input RPM ÷ Gear Ratio. For example, 1000 RPM input with a 2:1 ratio gives 500 RPM output.

How do I calculate output torque? Output Torque = Input Torque × Gear Ratio × Efficiency. For example, 100 N·m input with a 2:1 ratio and 98% efficiency gives 196 N·m output.