Gear Ratio Calculation Made Simple! Understanding gear ratio is essential for every mechanical engineer, maintenance professional, and engineering student. Given: Driver Gear (Z₁) = 12 Teeth Driver Speed (N₁) = 1200 RPM Driven Gear (Z₂) = 36 Teeth Formula: Gear Ratio = Z₂ / Z₁ = N₁ / N₂ Calculation: Gear Ratio = 36 ÷ 12 = 3:1 Driven Speed (N₂) = 1200 ÷ 3 = 400 RPM Key Learning: As the gear ratio increases, the output speed decreases while the output torque increases—one of the fundamental principles of power transmission. Save this post for quick revision and share it with fellow engineers! Post navigation Comprehensive Compound Gear Train Velocity Analysis