Torque Converter
Convert between various units of torque, including newton meters, foot-pounds, inch-pounds, and more.
About Torque Units
Torque, also known as moment of force, is the rotational equivalent of linear force. It measures the tendency of a force to rotate an object around an axis. The SI unit of torque is the newton meter (N·m), which is equal to the torque produced by a force of one newton applied perpendicularly to a moment arm of one meter length.
Common Torque Units
- Newton meter (N·m): The SI unit of torque. Represents the torque resulting from a force of one newton applied perpendicularly at a distance of one meter from the axis of rotation.
- Foot-pound (ft·lb or ft·lbf): A unit commonly used in the United States and the UK. One foot-pound is the torque created by a force of one pound applied at a perpendicular distance of one foot from the axis of rotation.
- Inch-pound (in·lb or in·lbf): Similar to the foot-pound but using inches instead of feet. Commonly used for lower torque values.
- Kilogram meter (kg·m): A non-SI unit representing the torque produced by a force of one kilogram-force applied at a perpendicular distance of one meter.
- Dyne centimeter (dyn·cm): A unit in the CGS system. Equal to 10-7 N·m.
- Newton centimeter (N·cm): Equal to 0.01 N·m. Used for smaller torque measurements.
Torque Formula
Torque (τ) is calculated as the cross product of the position vector (r) and the force vector (F):
Where τ is torque, r is the position vector (distance from axis of rotation), F is the force vector, and θ is the angle between r and F. The magnitude is maximum when the force is applied perpendicular to the lever arm (θ = 90°).
Typical Torque Values
| Application | Typical Torque Range | Notes |
|---|---|---|
| Screwdriver (hand-tight) | 1-3 N·m | Manual tightening of small screws |
| Bicycle wheel nuts | 15-20 N·m | Standard tightening for wheel axle nuts |
| Car wheel lug nuts | 100-150 N·m | Secures wheels to vehicle axle |
| Small car engine | 100-200 N·m | Peak torque output of 1.0-1.5L engines |
| Sports car engine | 400-600 N·m | High-performance vehicle engines |
| Heavy-duty truck engine | 1,500-3,000 N·m | Diesel engines for commercial trucks |
| Industrial turbine | 10,000+ N·m | Large power generation equipment |
Torque Applications
- Automotive Engineering: Engine torque is a key performance metric for vehicles, indicating their ability to accelerate or haul heavy loads.
- Mechanical Fastening: Proper torque is essential for tightening bolts, nuts, and screws to ensure they're secure without being damaged.
- Industrial Machinery: Torque measurements are crucial for designing and maintaining equipment with rotating parts.
- Robotics: Torque control in robotic joints allows for precise movements and interaction with the environment.
- Sports Equipment: In golf, tennis, and other sports, the torque applied to equipment affects performance significantly.
- Power Tools: Torque settings on drills, screwdrivers, and wrenches help prevent damage to fasteners and materials.
Torque and Power Relationship
In rotational systems, power (P) is related to torque (τ) and angular velocity (ω) by:
Where P is in watts, τ is in newton meters, and ω is in radians per second. Using RPM (revolutions per minute) instead:
Torque vs. Force
While force causes an object to accelerate linearly according to F = ma, torque causes an object to rotate with an angular acceleration according to τ = Iα, where:
- τ (tau) is the torque
- I is the moment of inertia (resistance to rotational acceleration)
- α (alpha) is the angular acceleration
Torque Wrench Use Tips
When using a torque wrench for mechanical work:
- Always consult manufacturer specifications for the correct torque value
- Apply torque in a smooth, continuous motion until the set value is reached
- Tighten fasteners in a criss-cross or star pattern when working on components with multiple bolts
- Release the tension on the torque wrench when storing to maintain calibration
- Recalibrate torque wrenches periodically to ensure accuracy