Torque Calculator
Calculate torque from force and lever arm distance. Convert between N·m, lb-ft, and lb-in. Perpendicular force assumed (90° angle).
Results
—N·m
Pound-feet—
Pound-inches—
Kilogram-meters—
Formula Used
τ = F × d
What Is Torque?
Torque is a rotational force that causes an object to rotate around an axis. It is the product of force applied at a distance from the pivot point (lever arm). Torque determines how effectively a force can produce rotation.
The SI unit of torque is the Newton-meter (N·m). In the US customary system, torque is measured in pound-feet (lb-ft) or pound-inches (lb-in).
Torque Formula
Torque Equation
τ = F × d × sin(θ)
Where τ is torque, F is force, d is the perpendicular distance from the axis, and θ is the angle between the force and lever arm. When force is applied at 90° (perpendicular), sin(90°) = 1, simplifying to τ = F × d.
Torque Unit Conversion
| From | To N·m | To lb-ft | To lb-in |
|---|---|---|---|
| 1 N·m | 1 | 0.7376 | 8.851 |
| 1 lb-ft | 1.3558 | 1 | 12 |
| 1 lb-in | 0.1130 | 0.0833 | 1 |
| 1 kgf·m | 9.807 | 7.233 | 86.80 |
Common Bolt Torque Specifications
| Bolt Size | Grade 5 (lb-ft) | Grade 8 (lb-ft) |
|---|---|---|
| 1/4" | 8 | 12 |
| 5/16" | 17 | 24 |
| 3/8" | 31 | 44 |
| 7/16" | 49 | 70 |
| 1/2" | 75 | 105 |
| 9/16" | 110 | 155 |
| 5/8" | 150 | 210 |
| 3/4" | 260 | 380 |
Torque Calculator FAQ
Torque is rotational force = Force × Distance from axis. Measured in N·m, lb-ft, or lb-in.
τ = F × d × sin(θ). For perpendicular force (most cases), τ = F × d.
Multiply N·m by 0.7376. Example: 100 N·m = 73.76 lb-ft.