What's the difference between gear ratio and mechanical advantage?
Gear ratio is the tooth count ratio. Mechanical advantage is the theoretical torque multiplication (ratio × efficiency).
Engineering
Gear Ratio Calculator
Calculate gear ratios, output speeds, and torque relationships for mechanical systems.
Gear System Analysis
Analyze gear pairs to determine speed and torque relationships with efficiency considerations.
%
What this calculator does
A gear ratio calculator determines how gears modify speed and torque between input and output shafts. Gear trains let motors operating at high speed and low torque become slow-speed, high-torque outputs. Understanding ratios is essential in automotive, industrial, and robotics applications.
How it works
The calculator takes tooth counts on driving and driven gears, plus input speed and torque. Gear ratio = driven teeth ÷ driving teeth. Output speed = input speed ÷ ratio; output torque = input torque × ratio × efficiency.
Formula
Gear Ratio = Driven Teeth ÷ Driving Teeth. Output Speed = Input Speed ÷ Ratio. Output Torque = Input Torque × Ratio × Efficiency. Power = (Torque × Speed × 2π) / 60,000 (kW).
Tips for using this calculator
- Gear ratio is conserved—3:1 ratio always reduces speed by 3× and increases torque by 3×
- Typical mechanical efficiency is 95-98% per stage
- Match output requirements to application—undersizing creates excessive load
- Larger teeth and slower speeds improve efficiency
- Compound gear trains allow fine-tuning ratios
Frequently asked questions
Can I achieve high ratios with a single gear pair?
Practically limited to 5:1-8:1 before gear size becomes impractical. Higher ratios require multiple stages or planetary gears.
Why does efficiency matter?
Efficiency determines how much input power reaches output. In multi-stage systems, losses compound: three 98% stages = 94% overall.