What Is Torque and How Is It Calculated?
Torque, also called the moment of force, is a measure of the rotational force applied to an object around a pivot point. It is calculated by multiplying the applied force by the length of the lever arm and the sine of the angle between them, expressed as newton-meters (N·m) or pound-feet (lb·ft).
The torque formula is: τ = F × r × sin(θ), where τ is torque, F is the applied force, r is the distance from the pivot point to where the force is applied (the lever arm), and θ is the angle between the force vector and the lever arm. When force is applied perpendicular to the lever arm, θ = 90° and sin(θ) = 1, so torque simplifies to τ = F × r.
According to standard mechanical engineering references, torque wrenches used in automotive and industrial work are typically calibrated in newton-meters or pound-feet, with common bolt-tightening specifications ranging from 10 N·m for small fasteners to over 500 N·m for wheel lug nuts and heavy machinery bolts.
How to Use This Torque Calculator
Enter your force, lever arm length, and angle, and the calculator updates the torque instantly. Here's what each field means:
- Applied Force: The push or pull force at the end of the lever arm, in newtons (N) or pound-force (lbf). This is what you're exerting on a wrench, pedal, or handle.
- Lever Arm Length: The distance from the pivot point (fulcrum) to where the force is applied, in meters (m) or feet (ft). A longer lever arm multiplies the resulting torque for the same force.
- Angle: The angle between the direction of the force and the lever arm, in degrees. Use 90° for a force applied straight-on (perpendicular) — the most common and most efficient case.
This calculator works in both metric (newtons and meters) and imperial (pound-force and feet) units, and converts results to newton-meters, pound-feet, pound-inches, and kilogram-force-meters so you can match whatever unit your torque wrench or textbook specifies.
Common Torque Calculator Units and Conversions
Torque specifications vary by industry and region, so this calculator converts your result into the four most commonly used units side by side.
| Unit | Symbol | Typical Use |
|---|---|---|
| Newton-meter | N·m | SI standard, engineering and physics |
| Pound-foot | lb·ft | US automotive engine and wheel specs |
| Pound-inch | lb·in | Small fasteners, electronics assembly |
| Kilogram-force-meter | kgf·m | Common in some Asian and European manuals |
Frequently Asked Questions
What is a good example of torque in everyday life?
Turning a wrench to tighten a bolt is the classic torque example: applying 40 N of force at the end of a 0.25 m wrench handle, perpendicular to the handle, produces 10 N·m of torque. Opening a door, pedaling a bicycle, and using a screwdriver are other everyday applications of torque.
How accurate is this torque calculator?
This calculator applies the standard torque formula τ = F × r × sin(θ) exactly, so results are as accurate as the force, distance, and angle values you enter. It assumes a rigid lever arm and a single applied force; it does not account for friction, material flex, or multiple simultaneous forces.
What is the difference between torque and force?
Force is a straight-line push or pull measured in newtons or pounds, while torque is a rotational effect measured in newton-meters or pound-feet. The same force produces different torque depending on how far from the pivot point it is applied and at what angle.
How do I increase torque without increasing force?
Increase the lever arm length or apply the force closer to 90° from the arm. Doubling the lever arm length doubles the torque for the same applied force, which is why breaker bars and longer wrenches make it easier to loosen stubborn bolts.