Torque Conversion

High‑accuracy conversion between 7+ torque units: Newton meters (Nm), pound‑force feet (lb·ft), pound‑force inches (lb·in), kilogram‑force meters (kgf·m), ounce‑force inches (oz·in), kilonewton meters (kNm), and dyne centimeters (dyn·cm).

Quick examples:
1 Nm → lb·ft
100 lb·ft → Nm
50 lb·in → Nm
10 kgf·m → Nm
88 oz·in → lb·in
2.5 kNm → lb·ft
0.00 Nm
Precision: 6 decimal places
Local & secure: All conversions run inside your browser. No data is uploaded or stored.

Understanding Torque: Physics, Engineering & Conversion Principles

Torque (moment of force) is the rotational equivalent of linear force. It quantifies the tendency of a force to rotate an object about an axis, fulcrum, or pivot. Expressed in newton meters (Nm) in the SI system, torque is fundamental in mechanical design, automotive engineering, aerospace, and structural analysis. Precise unit conversion ensures safety and accuracy in fastener tightening, engine tuning, and robotic joint actuation.

τ = r × F   →   |τ| = r · F · sinθ

where r = lever arm length, F = applied force, θ = angle between force vector and lever arm.

Torque Unit Reference & Conversion Factors

Unit Symbol Equivalent in Nm (exact / defined) Common use
Newton meter Nm 1 SI standard, engineering, physics
Kilonewton meter kNm 1000 Large structures, wind turbines, heavy machinery
Pound-force foot lb·ft 1.3558179483314004 Automotive torque, engines, imperial fasteners
Pound-force inch lb·in 0.1129848290276167 Small fasteners, precision assemblies
Kilogram-force meter kgf·m 9.80665 Metric engineering (older standards), Europe/Asia
Ounce-force inch oz·in 0.007061551814424 Electronic assembly, miniature torque tools
Dyne centimeter dyn·cm 1e-7 CGS unit, micro-mechanics, physics labs
Conversion logic: All values are first normalized to newton meters (Nm) using precise factors, then converted to the target unit. Factors comply with NIST and ISO 80000‑4 standards.

Why Use This Torque Converter?

  • ⚙️ Engineering-grade accuracy – 15 decimal internal precision, rounding to 6 decimals for practical readability.
  • ? Real-time bidirectional conversion – Swap units instantly and recalculate.
  • ? Comprehensive unit coverage – From micro torque (dyn·cm) to heavy-duty kNm, plus kgf·m and imperial measures.
  • ? Integrated learning – Explore torque physics, fastener classes, and real‑world case studies below.
Case Study: Engine Fastener Torque Specification

A Formula 1 engine cylinder head requires bolts to be tightened to exactly 65 Nm + 90° angle. Using our converter, a technician calibrates a torque wrench originally marked in lb·ft: 65 Nm converts to approximately 47.94 lb·ft. The conversion ensures compliance with manufacturer standards and prevents gasket failure. Likewise, aerospace fasteners often list torque in lb·in; converting to Nm allows consistent international maintenance procedures. Reliable unit conversion directly impacts safety and performance.

Step‑by‑Step Conversion Workflow

  1. Enter the numeric torque value (positive or negative magnitude — direction not required for scalar conversion).
  2. Select the source unit from the dropdown (e.g., lb·ft).
  3. Select the target unit (e.g., Nm).
  4. The converter instantly displays the equivalent value with up to 6 decimal precision.
  5. Use the swap icon ⇄ to exchange source and target units for reverse conversion.

Common Torque Applications & Industry Benchmarks

Application Typical Torque Range Unit preference
Bicycle pedal installation 30–40 Nm Nm / lb·ft
Automotive wheel lug nuts 80–120 lb·ft (108–163 Nm) lb·ft
Small electronics screws 3–12 oz·in (0.02–0.085 Nm) oz·in / cN·m
Structural steel bolts (M20 grade 8.8) 480–580 Nm Nm / kNm
Electric motor mounting 5–25 Nm Nm / lb·in

History & Standards: Evolution of Torque Measurement

Torque as a physical concept was formalized by Archimedes (lever principle) and later by Simon Stevin. The modern SI unit, the newton meter, honors Sir Isaac Newton. Throughout the industrial revolution, imperial units like pound‑foot dominated English‑speaking countries. Today, global engineering integrates both systems; standards such as ASME B107.300 and ISO 6789 define torque tool calibration. Our converter uses the internationally accepted conversion factors published by NIST (National Institute of Standards and Technology).

Expert Tips for Torque Conversion Accuracy

  • Always respect significant figures: Torque wrenches have accuracy classes (±4% typical). Rounded conversions are safe for practical use.
  • Know the difference: kgf·m vs. Nm – 1 kgf·m = 9.80665 Nm exactly (standard gravity).
  • Dynamic vs static torque: Our converter handles static torque magnitudes; dynamic peak torque may require additional instrumentation.
  • Unit confusion: Never confuse lb·ft with ft·lb (same dimension but often miswritten). We maintain consistent notation lb·ft.

Verified engineering reference – Conversion factors are derived from the International System of Units (SI) and authoritative engineering handbooks (Machinery's Handbook, 31st Edition). Reviewed by getzenquery Tech team. Last updated March 2026. For critical applications, always cross‑reference with certified torque equipment.

Frequently Asked Questions

Nm (newton meter) is the SI unit; lb·ft (pound-force foot) is the imperial unit for torque. 1 lb·ft = 1.355817948 Nm. Both measure rotational force.

This tool provides theoretical conversion values. Actual tightening requires calibrated torque tools. Always follow manufacturer torque specifications to avoid under‑ or over‑tightening.

Yes, the absolute value is converted identically; sign indicates direction (clockwise/counter‑clockwise) and is preserved in the result.

Our converter uses high-precision factors (matching NIST). Some tools use rounded 1.356 for lb·ft to Nm, causing minor variations. For engineering purposes, we provide the exact value to 6 decimals.

Yes, kgf·m (kilogram-force meter) is often shortened to kg·m in some contexts. Both refer to the torque produced by 1 kilogram-force acting at 1 meter lever arm.
References: NIST Special Publication 811 (2008), ISO 80000-4:2019 Quantities and units — Mechanics, Machinery's Handbook 31st Edition. NIST SI Units • Torque (Wikipedia) • Engineering ToolBox