Torque & Gear Ratio Calculator
Calculate torque from force and lever arm, and a gear train's ratio, output speed and output torque from the tooth counts.
How to use
- 1For torque, enter the force, lever length and angle.
- 2For gears, enter the driving and driven tooth counts, input speed and input torque.
How it's calculated
Torque τ = F × r × sin θ. Gear ratio = driven teeth ÷ driving teeth. Output speed = input speed ÷ ratio; output torque = input torque × ratio (ignoring losses).
Frequently asked questions
How do gears trade speed for torque?
A larger driven gear turns more slowly but with more torque; power (speed × torque) stays the same apart from friction losses.
Why does the angle matter for torque?
Only the part of the force perpendicular to the lever turns it. Pushing straight along the wrench gives no torque.
How do I convert N·m to lb·ft?
1 N·m ≈ 0.7376 lb·ft. Use the torque converter for other units.