🔧 Torque Unit Converter

Convert between torque units for mechanics, engineering, and physics. Professional tool for automotive and rotational force calculations.

Converter
Common Units
Formulas
Examples
Guide

Torque Converter

Important Note: Torque is the rotational equivalent of force (τ = F × r × sin θ). It causes angular acceleration about an axis. Critical for proper fastener tension, motor specifications, and mechanical safety.

Common Torque Units

Newton-meter
N⋅m

SI unit of torque. 1 N⋅m = 1 kg⋅m²/s². Standard in engineering and physics calculations.

Pound-foot
lb⋅ft

Imperial torque unit. Common in US automotive and mechanical engineering applications.

Kilogram-meter
kg⋅m

Metric technical unit. 1 kg⋅m = 9.80665 N⋅m. Used in some mechanical specifications.

Pound-inch
lb⋅in

Small torque applications. Common for fasteners, electronics, and precision assemblies.

Ounce-inch
oz⋅in

Micro-torque applications. Used for delicate instruments and small mechanical devices.

Kilonewton-meter
kN⋅m

Large torque applications. Industrial machinery, heavy equipment, and structural engineering.

Torque Conversion Table

Unit Newton-meter (N⋅m) Pound-foot (lb⋅ft) Pound-inch (lb⋅in) Common Application
1 Newton-meter10.7388.851SI standard, physics
1 Pound-foot1.356112US automotive, mechanical
1 Kilogram-meter9.8077.23386.8Metric engineering
1 Pound-inch0.1130.08331Small fasteners, electronics
1 Ounce-inch0.007060.005210.0625Micro-torque, precision
1 Kilonewton-meter1,000737.68,851Industrial machinery

Torque Formulas & Calculations

Basic Torque Formula
τ = F × r × sin(θ)
Torque = Force × Distance × sin(angle)

Fundamental torque equation. F is applied force, r is distance from axis, θ is angle between force and radius.

Angular Acceleration
τ = I × α
Torque = Moment of inertia × Angular acceleration

Rotational equivalent of Newton's second law. Relates torque to angular motion.

Rotational Power
P = τ × ω
Power = Torque × Angular velocity

Power in rotational systems. ω is angular velocity in rad/s.

Rotational Work
W = τ × θ
Work = Torque × Angular displacement

Work done by torque through angular displacement θ (radians).

Torsional Stress
τ = Tr/J
Shear stress = Torque × radius / Polar moment

Stress in rotating shafts. T is torque, r is radius, J is polar moment of inertia.

Gear Ratio Torque
τ₂ = τ₁ × (N₁/N₂)
Output torque = Input torque × Gear ratio

Torque transformation through gear systems. N₁/N₂ is gear ratio.

Angular Motion Relationships

Quantity Linear Motion Rotational Motion Relationship
Force/TorqueForce (F)Torque (τ)τ = F × r
Mass/InertiaMass (m)Moment of inertia (I)I = mr²
AccelerationLinear (a)Angular (α)a = α × r
VelocityLinear (v)Angular (ω)v = ω × r
MomentumLinear (p = mv)Angular (L = Iω)L = r × p
Kinetic Energy½mv²½Iω²KE = ½Iω²
Important: Torque is a vector quantity with direction. Use right-hand rule to determine direction. Positive torque creates counterclockwise rotation when viewed from positive axis direction.

Torque Examples & Applications

🚗 Automotive Torque
  • Engine torque: 200-800 N⋅m (150-590 lb⋅ft)
  • Wheel lug nuts: 80-140 N⋅m (60-100 lb⋅ft)
  • Spark plugs: 15-30 N⋅m (11-22 lb⋅ft)
  • Oil drain plug: 25-35 N⋅m (18-26 lb⋅ft)
  • Cylinder head bolts: 60-120 N⋅m (44-89 lb⋅ft)
  • Brake caliper bolts: 100-150 N⋅m (74-111 lb⋅ft)
🏗️ Engineering & Construction
  • Structural bolts M20: 400-500 N⋅m (295-369 lb⋅ft)
  • Crane boom bolts: 1,000-5,000 N⋅m (738-3,688 lb⋅ft)
  • Bridge cable tension: 10-50 kN⋅m (7.4-36.9 klb⋅ft)
  • Wind turbine bolts: 2,000-10,000 N⋅m (1.5-7.4 klb⋅ft)
  • Heavy machinery bolts: 500-2,000 N⋅m (369-1,475 lb⋅ft)
  • Pipeline flanges: 200-800 N⋅m (148-590 lb⋅ft)
🔧 Precision & Electronics
  • Computer screws: 0.2-0.8 N⋅m (1.8-7.1 lb⋅in)
  • Watch screws: 0.01-0.05 N⋅m (0.09-0.44 lb⋅in)
  • Optical instruments: 0.1-0.5 N⋅m (0.9-4.4 lb⋅in)
  • Smartphone screws: 0.05-0.2 N⋅m (0.44-1.8 lb⋅in)
  • PCB mounting: 0.1-0.3 N⋅m (0.9-2.7 lb⋅in)
  • Jewelry fasteners: 0.01-0.1 N⋅m (0.09-0.9 lb⋅in)
⚙️ Industrial Machinery
  • Motor coupling: 100-1,000 N⋅m (74-738 lb⋅ft)
  • Pump shaft bolts: 200-600 N⋅m (148-443 lb⋅ft)
  • Gear box bolts: 300-1,200 N⋅m (221-885 lb⋅ft)
  • Conveyor drive: 500-3,000 N⋅m (369-2,212 lb⋅ft)
  • Press machine bolts: 1,000-5,000 N⋅m (738-3,688 lb⋅ft)
  • Turbine assembly: 2,000-20,000 N⋅m (1.5-14.8 klb⋅ft)

Torque by Material & Thread Size

🔩 Metric Bolts (Steel)

M6: 8-12 N⋅m (6-9 lb⋅ft)

M8: 18-25 N⋅m (13-18 lb⋅ft)

M10: 35-50 N⋅m (26-37 lb⋅ft)

M12: 60-85 N⋅m (44-63 lb⋅ft)

M16: 150-220 N⋅m (111-162 lb⋅ft)

M20: 290-420 N⋅m (214-310 lb⋅ft)

🔧 Imperial Bolts (Steel)

1/4": 8-12 N⋅m (6-9 lb⋅ft)

5/16": 18-25 N⋅m (13-18 lb⋅ft)

3/8": 35-50 N⋅m (26-37 lb⋅ft)

1/2": 85-120 N⋅m (63-89 lb⋅ft)

5/8": 170-240 N⋅m (125-177 lb⋅ft)

3/4": 290-410 N⋅m (214-302 lb⋅ft)

⚡ Material Factors

Stainless Steel: 60-80% of steel torque

Aluminum: 40-60% of steel torque

Brass: 50-70% of steel torque

Plastic: 10-30% of steel torque

Lubricated: 10-15% reduction

Thread locker: Follow manufacturer specs

Torque Guide & Best Practices

📏 Understanding Torque
  • Definition: Rotational force about an axis
  • Vector quantity: Has magnitude and direction
  • SI Unit: Newton-meter (N⋅m)
  • Effect: Causes angular acceleration
🎯 Types of Torque
  • Static torque: No rotation, equilibrium
  • Dynamic torque: Causes angular acceleration
  • Tightening torque: Fastener specifications
  • Breakaway torque: Required to start rotation
🌍 Applications by Field
  • Automotive: lb⋅ft, N⋅m specifications
  • Aerospace: High precision, in⋅lb
  • Electronics: oz⋅in, very low torque
  • Heavy Industry: kN⋅m, large torques
🔧 Measurement Tools
  • Torque wrench: Click-type, beam-type
  • Torque screwdriver: Precision assembly
  • Digital torque meter: Electronic measurement
  • Torque multiplier: High torque applications
⚠️ Common Mistakes
  • Over-tightening: Can strip threads or break
  • Under-tightening: Joint may loosen
  • Wrong sequence: Follow star/cross pattern
  • Dirty threads: Clean before assembly
🔄 Conversion Tips
  • Quick estimate: 1 lb⋅ft ≈ 1.36 N⋅m
  • Small torques: Use lb⋅in or oz⋅in
  • Precision: Use exact conversion factors
  • Context: Choose appropriate unit for scale

Torque Application Best Practices

Safety & Quality Tips:
  • Always use calibrated torque tools for critical applications
  • Follow manufacturer's torque specifications exactly
  • Apply torque in proper sequence (star pattern for multiple bolts)
  • Consider lubrication effects - reduce torque by 10-15% for lubricated threads
  • Account for material differences (stainless, aluminum require different torques)
  • Re-torque critical joints after initial settling period
  • Document torque values for quality control and maintenance