Gear Ratio Calculator
The Gear Ratio Calculator computes the mechanical advantage between meshing gears from tooth counts. Determine output RPM, torque multiplication, and overall gear train ratios for single-stage and compound systems.
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What is Gear Ratio?
Gear ratio is the ratio of teeth on the driven gear to teeth on the driving gear. A 60-tooth driven gear meshed with a 20-tooth driving gear creates a 3:1 ratio — the driving gear rotates 3 times for every 1 rotation of the driven gear, tripling torque while reducing speed by one-third.
Gear ratios are fundamental in automotive transmissions, industrial gearboxes, clock mechanisms, bicycle drivetrains, and robotics. Understanding gear ratios allows engineers to match motor speed and torque to application requirements precisely.
Formules et Équations utilisées
Ce calculateur s'appuie sur 5 équations fondamentales :
1 Gear Ratio ▼
Driven (60 teeth) / Driver (20 teeth) = 3:1 ratio.
2 Output RPM ▼
Input 3600 RPM with 3:1 ratio: Output = 3600 / 3 = 1200 RPM.
3 Compound Gear Train Ratio ▼
Two stages of 3:1 and 4:1: Overall = 3 × 4 = 12:1 total reduction.
Comment utiliser ce calculateur
Pour utiliser ce Calculateur de Ratio, suivez ces 3 étapes :
Saisir les Valeurs
Saisissez les valeurs de ratio connues dans les champs. Laissez un champ vide — c'est la valeur manquante que le calculateur va chercher à résoudre.
Choisir le Mode
Sélectionnez le mode de ratio — Résoudre, Simplifier ou Mettre à l'échelle. Chaque mode applique des formules différentes à vos valeurs.
Obtenir les Résultats
Cliquez sur Calculer. L'écran de résultats affiche la réponse avec une barre de ratio interactive, un diagramme circulaire et le détail des calculs.
Exemples Pratiques et Solutions Étape par Étape
Voici 3 exemples de calculs résolus avec les étapes détaillées grâce à ce calculateur :
Saisie 1 40-tooth gear driven by 10-tooth pinion
Saisie 2 Motor at 1800 RPM through 5:1 gearbox
Saisie 3 Two-stage reducer: 3:1 and 4:1
Foire Aux Questions
What does a higher gear ratio mean? ▼
A higher gear ratio (like 5:1 vs 2:1) means more speed reduction and more torque multiplication. The driving gear spins more times per output rotation. This is common in first gear of transmissions for starting from a stop.
How do compound gear trains work? ▼
Compound trains stack multiple gear pairs. Each pair's ratio is multiplied together. Three stages of 3:1 each give 3³ = 27:1 overall ratio. This allows massive speed reductions in a compact package.
What is a gear reduction vs overdrive? ▼
Reduction means the output is slower than input (ratio > 1). Overdrive means output is faster than input (ratio < 1). Cars use overdrive gears (like 0.75:1) for highway fuel economy.
How do I calculate gear ratio for a specific output speed? ▼
Gear Ratio = Input RPM / Desired Output RPM. To get 500 RPM from a 3000 RPM motor: Ratio = 3000/500 = 6:1. Then choose gear teeth: 12T driver / 72T driven = 6:1.
Does gear ratio affect power output? ▼
No. Power (watts) is conserved through the gear train (minus friction losses of 1-5% per stage). A 3:1 ratio multiplies torque by 3× but divides speed by 3×. Power = Torque × Speed remains constant.