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🔧 Torque Converter

Convert between N·m, kgf·m, and lbf·ft

Newton-meter (N·m)9.80665
Kilogram-force meter (kgf·m)1
Pound-force foot (lbf·ft)7.23300291
* Conversion: 1 kgf·m = 9.80665 N·m, 1 lbf·ft = 1.35582 N·m
* Torque = Force × Lever arm; 1 N·m means the torque produced by 1 N of force at a 1 m lever arm

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Torque Converter Instructions

The torque converter supports conversion between three commonly used torque units: Newton-meter (N·m), kilogram-force meter (kgf·m), and pound-force foot (lbf·ft).

Torque (also called moment) is the measure of a force's tendency to rotate an object about an axis, with the formula τ = F × r (force × lever arm). It is widely used in automotive engine specifications, mechanical fastener specifications, and motor selection. This tool helps you quickly convert between metric (N·m), engineering (kgf·m), and imperial (lbf·ft) units.

Torque Unit Conversion Relationships

【International System of Units (SI)】
1 N·m = 1 N × 1 m
1 kN·m = 1000 N·m

【Engineering Units】
1 kgf·m = 9.80665 N·m ≈ 9.81 N·m
(Torque produced by 1 kgf at a 1 m lever arm)

【Imperial Units】
1 lbf·ft = 1.35582 N·m ≈ 1.36 N·m
1 lbf·in = 0.112985 N·m ≈ 0.113 N·m
Note: 1 lbf·ft = 12 lbf·in

【Reference Values】
Household wrench handle length typically 30 cm → 100 N force produces 30 N·m torque
Bicycle pedal: rider produces approximately 50-100 N·m

Conversion Examples

📋
【Example 1】Automotive engine torque VW 2.0T engine: 350 N·m = 35.7 kgf·m = 258.3 lbf·ft F1 racing engine: approximately 300-400 N·m (but at 18,000 rpm → power exceeds 1000 hp) 【Example 2】Bolt tightening specifications M12 bolt recommended torque: 80-120 N·m = 8.15-12.24 kgf·m = 59-88 lbf·ft Requires a torque wrench for precision 【Example 3】Motor selection Servo motor rated at 5 N·m = 0.51 kgf·m = 3.69 lbf·ft Can drive a small conveyor belt or robotic arm joint 【Example 4】Daily scenarios Wringing a towel wrist torque: approximately 5-10 N·m Opening a bottle cap: approximately 2-5 N·m (depending on seal tightness)

Important Notes

💡
- Torque and power are different but related: P = τ × ω (power = torque × angular velocity); at the same torque, higher rpm means more power - The "maximum torque" in car specifications is achieved at a specific rpm, not maintained across the entire rpm range - Torque wrenches have accuracy grades; important fasteners require regular calibration - lbf·ft and lbf·in differ by a factor of 12; be careful not to mix up the unit magnitudes - "Pound-foot" (lb-ft) and "foot-pound" (ft-lb) have the same meaning but different writing conventions

Application Scenarios

  • - Car shopping: Compare torque parameters of different models to judge acceleration and climbing ability
  • - Mechanical assembly: Tighten bolts to specified torque values (too loose = detachment, too tight = breakage)
  • - Motor selection: Choose a drive motor with the appropriate rated torque based on load requirements
  • - Sports science: Golf swing and baseball batting torque analysis
  • - Tool selection: Purchase a torque wrench or electric screwdriver with the appropriate range

Torque and Daily Life

The most intuitive way to understand torque is pushing a door — the farther the door handle is from the hinge, the easier it is to push the door with the same force. This is why door handles are installed at the edge of the door rather than near the hinges: a larger lever arm (r) means the same force (F) produces greater torque (τ = F × r).

Another interesting example is the lever principle: Archimedes said, "Give me a fulcrum, and I shall move the Earth." Theoretically, with a long enough lever, a very small force could generate enough torque to move any heavy object. Of course, infinitely long rigid rods don't exist in reality, but this perfectly illustrates the physical essence of torque.

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