Torque Calculator

τ = r × F × sin(θ). Rotational force = lever arm × applied force × angle.

Inputs

Result

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General calculation reads

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How to use this calculator

  • Enter lever arm + force + angle.
  • Read torque in N·m and lb-ft.

About this calculator

Torque (τ) is rotational force. τ = r × F × sin(θ) where r = lever arm, F = applied force, θ = angle between them. Maximum torque at θ = 90° (perpendicular). Wrench: longer lever = more torque for same hand force. Engine torque is at the crankshaft. Standard wheel-lug torque spec: 100-150 lb-ft for passenger cars; 350+ for heavy trucks. SI unit N·m; US engineering uses lb-ft.

Frequently asked

Why sin θ?+
Only the perpendicular component of force creates torque. F sin θ is that perpendicular component.
Maximum torque?+
When force is perpendicular to lever (θ = 90°, sin θ = 1).
Why does longer wrench help?+
τ = r × F. Doubling r halves the F you need for same τ. Cheater bars exist for stuck bolts.
Engine torque vs. HP?+
τ = HP × 5252 / RPM (US units). Diesels: high τ at low RPM. Race engines: less τ but at very high RPM.
Wheel torque spec?+
Owner manual or QR sticker on door jamb. Typical: 80-100 ft-lb compact, 110-140 mid-size, 150+ trucks.

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