Torque in Foot-Pounds Calculator
Calculate torque in foot-pounds with precision. Perfect for engineering, physics, and mechanical applications.
Torque Calculator
Torque Formula
The torque (τ) created by a force is calculated using the following formula:
τ = F × d × sin(θ)
Where:
- τ is the torque in foot-pounds (ft-lbs)
- F is the applied force in pounds (lbs)
- d is the lever arm distance in feet (ft)
- θ is the angle between the force vector and the lever arm
Note: When the force is perpendicular to the lever arm (θ = 90°), sin(θ) = 1, so the torque is simply F × d.
Torque Visualization
This visualization shows how torque works:
- The blue line represents the lever arm
- The red arrow shows the direction and magnitude of the force
- The green arc indicates the resulting torque
The diagram updates as you change the values in the calculator.
Common Examples
Wrench Tightening
50 lbs force on a 2 ft wrench at 90 degrees
Door Opening
25 lbs force on a 3.5 ft door at 60 degrees
Wheel Turning
75 lbs force on a 1.5 ft steering wheel at 90 degrees
What is Torque?
Torque is a measure of the force that can cause an object to rotate about an axis. It is a twisting or turning force that tends to cause rotation. The concept is similar to that of a force, which causes linear acceleration, but torque causes angular acceleration.
In physics and mechanics, torque is represented as a vector quantity, with both magnitude and direction. The SI unit for torque is the newton meter (N⋅m). In the imperial system, torque is often measured in foot-pounds (ft-lbs).
Real-world Applications
Torque has numerous practical applications in everyday life and engineering:
- Automotive Engineering: Engine torque determines how quickly a vehicle can accelerate. Torque specifications are crucial when tightening bolts and nuts in engines and other mechanical systems.
- Construction: Proper torque application ensures structural integrity when fastening components.
- Home Maintenance: Applying the correct torque when installing fixtures prevents damage and ensures stability.
- Sports Equipment: In golf, tennis, and baseball, torque influences the power and control of swings.
Factors Affecting Torque
Three main factors influence the amount of torque generated:
- Force Magnitude: The greater the force applied, the greater the torque.
- Lever Arm Distance: The longer the lever arm (distance from the axis of rotation to the point where force is applied), the greater the torque.
- Angle of Force Application: Maximum torque occurs when the force is applied perpendicular (90°) to the lever arm. As the angle decreases or increases from 90°, the torque decreases accordingly.
Torque Unit Conversion Table
| From | To Foot-Pounds (ft-lbs) | To Newton-Meters (N⋅m) | To Inch-Pounds (in-lbs) |
|---|---|---|---|
| 1 Foot-Pound (ft-lb) | 1 | 1.3558 | 12 |
| 1 Newton-Meter (N⋅m) | 0.7376 | 1 | 8.8507 |
| 1 Inch-Pound (in-lb) | 0.0833 | 0.113 | 1 |
| 1 Kilogram-Meter (kg⋅m) | 7.233 | 9.807 | 86.796 |
| 1 Ounce-Inch (oz⋅in) | 0.0052 | 0.007 | 0.0625 |
Use this table to convert between common torque units. For example, to convert from Newton-meters to foot-pounds, multiply by 0.7376.
Frequently Asked Questions
What is the difference between torque and work?
Torque and work are related but distinct physical concepts. Torque is a measure of rotational force, causing an object to rotate around an axis. It’s measured in foot-pounds (ft-lbs) or newton-meters (N⋅m). Work, on the other hand, measures energy transfer when a force moves an object through a distance. While they share similar units, torque is a vector (having both magnitude and direction) that causes rotation, whereas work is a scalar quantity representing energy transfer in linear motion.
Why does torque depend on the angle of force application?
The angle of force application affects torque because only the component of force perpendicular to the lever arm contributes to rotation. When force is applied at 90° to the lever arm, all of the force contributes to creating torque. As the angle deviates from 90°, less force contributes to rotation, which is mathematically represented by the sin(θ) term in the torque equation. At 0° or 180°, when force is parallel to the lever arm, no torque is generated because sin(0°) = sin(180°) = 0.
How is torque used in automotive specifications?
In automotive specifications, torque refers to the rotational force produced by a vehicle’s engine. It’s typically measured in foot-pounds (ft-lbs) or newton-meters (N⋅m) and represents the engine’s ability to perform work. High torque at low RPMs provides good acceleration and pulling power, which is why trucks and vehicles designed for towing often prioritize torque over horsepower. Additionally, automotive maintenance requires precise torque specifications when tightening fasteners to ensure they’re secure without being damaged.
Can torque be negative?
Yes, torque can be negative. The sign of torque (positive or negative) indicates the direction of rotation. By convention, counterclockwise torque is often considered positive, while clockwise torque is negative, though this convention may vary depending on the coordinate system used. The sign doesn’t mean the torque is “less effective” – it simply indicates direction. In calculations, negative torque is just as powerful as positive torque of the same magnitude, just acting in the opposite rotational direction.
How do I convert between different torque units?
To convert between torque units, use these conversion factors:
- Foot-pounds (ft-lbs) to Newton-meters (N⋅m): multiply by 1.3558
- Newton-meters (N⋅m) to Foot-pounds (ft-lbs): multiply by 0.7376
- Foot-pounds (ft-lbs) to Inch-pounds (in-lbs): multiply by 12
- Inch-pounds (in-lbs) to Foot-pounds (ft-lbs): divide by 12
You can refer to the conversion table above for more conversions between common torque units.
Related Physics & Engineering Calculators
Free online physics and engineering calculators to convert and calculate distance, velocity, force, pressure, work, and other physical quantities in foot-based units.
Distance Traveled in Feet per Second
Calculate distance based on velocity in feet per second and elapsed time.
Velocity Conversion to Feet per Minute
Convert velocity measurements to feet per minute from other common units.
Acceleration in Feet per Second Squared
Calculate and convert acceleration values in ft/s² and other units.
Force in Pounds per Square Foot
Calculate force distribution across an area measured in pounds per square foot.
Pressure in Pounds per Square Foot
Convert and calculate pressure values in pounds per square foot (psf).
Work Done in Foot-Pounds
Calculate mechanical work in the foot-pound unit based on force and distance.
Torque in Foot Pounds
Calculate rotational force in foot-pounds for mechanical applications.
Height of a Projectile in Feet
Calculate maximum height and trajectory of a projectile measured in feet.
Flow Rate in Cubic Feet per Second
Calculate and convert fluid flow rates in cubic feet per second (CFS).
Heat Transfer Area in Square Feet
Calculate heat exchange surface area requirements in square feet.