⚙️ Advanced Gear Ratio Calculator
📐 “gear ratio calculator” — universal & precise
A gear ratio defines the mechanical relationship between input and output speed/torque. Used worldwide in automotive, bicycles, industrial machinery, and robotics. This advanced tool computes ratio, torque multiplication, speed reduction, and real-world vehicle speed based on tire size & final drive. Supports both metric (km/h) and imperial (mph) standards, aligning with ISO, DIN, AGMA (USA) and JIS norms. Adjust teeth, RPM, tire diameter — get instant insights with interactive graph.
A gear ratio defines the mechanical relationship between input and output speed/torque. Used worldwide in automotive, bicycles, industrial machinery, and robotics. This advanced tool computes ratio, torque multiplication, speed reduction, and real-world vehicle speed based on tire size & final drive. Supports both metric (km/h) and imperial (mph) standards, aligning with ISO, DIN, AGMA (USA) and JIS norms. Adjust teeth, RPM, tire diameter — get instant insights with interactive graph.
Smaller gear = higher input speed
Larger gear = torque increase, speed reduction
Engine / motor revolutions per minute
World standard: inches (1″ = 25.4 mm). Common car tires: 24–30″
Final reduction (e.g., diff ratio). 1 = direct, typical 2.5–5.0 in vehicles
📐 Gear Ratio (Teeth Ratio)Standard worldwide
— : 1
Ratio = Driven / Drive. >1 = reduction (torque up, speed down). According to AGMA (USA) & ISO 6336: higher ratios increase torque capacity but reduce output speed.
⚡ Overall Drivetrain RatioFinal drive included
— : 1
Overall = (Driven/Drive) × Final Drive. Affects final wheel torque and top speed.
🔁 Torque Multiplier FactorMechanical advantage
— x
Ideal torque increase (ignoring friction). For each 1 Nm input, output torque = ratio × input. USA standards: greater ratio improves launch acceleration.
⏱️ Output Shaft SpeedRPM after gearbox
— RPM
Output RPM = Input RPM / Gear Ratio. Speed reduction inversely proportional to torque gain.
🚀 Vehicle Speedmph
—
Based on tire circumference, overall ratio & input RPM. Worldwide formula: km/h or mph.
📉 Speed Reduction Factor1 / Ratio
—
Output speed relative to input. Factor <1 indicates speed reduction, >1 overdrive (common in high gears).
📊 ADVANCED ANALYSIS: Torque & Speed Modification (relative to input)
🌎 *Universal application: results reflect mechanical behavior for any country (metric & imperial). US (AGMA) emphasizes torque/speed trade-off; ISO & DIN define similar principles. This graph shows how overall ratio impacts output torque (higher = more pulling force) and output speed (lower = slower top end).*
📌 Global gear ratio insights: Used in automotive (USA, Europe, Asia), bicycles, wind turbines. Higher ratio → climbing torque, lower top speed. Lower ratio (overdrive) → better fuel economy at highway speeds. Tire size affects final speed: larger diameter increases speed per RPM. This calculator adapts to both SAE (inches) & SI (km/h).