Torque Converter

Free Online Torque Converter — N·m, lb-ft, lb-in, kgf·m and More

Torque is the rotational equivalent of force — the measure of how much a force acting on a lever arm tends to cause rotation around an axis. It appears in engine specifications, fastener tightening requirements, electric motor ratings, bicycle bottom bracket calculations, and virtually any engineering context involving rotation or tightening. The diversity of torque unit conventions across different industries and countries creates constant conversion needs: automotive engineers work in Newton-meters (N·m) or pound-feet (lb·ft), small electronics engineers specify torque in ounce-inches (oz·in), and some older references use kilogram-force meters (kgf·m). Our free online torque converter handles all of these unit families, delivering instant accurate conversions without requiring you to remember the specific conversion factors.

What Is Torque and How Is It Measured?

Torque (also called moment or moment of force) is defined as the product of a force and the perpendicular distance from the rotation axis to the line of action of that force. The mathematical expression is τ = F × r × sin(θ), where F is the force magnitude, r is the distance from the pivot to the point of force application, and θ is the angle between the force vector and the lever arm. For the simplest case where force is applied perpendicular to the lever arm (θ = 90°, sin(90°) = 1), torque equals force times distance directly: τ = F × r.

The dimensional analysis reveals why torque has the same units as energy (both are force × distance), yet they are fundamentally different physical quantities. Energy (work) is a scalar — it has magnitude but no direction. Torque is a vector — it has both magnitude and a direction (the axis about which rotation occurs). One newton-meter of torque and one joule of energy share unit dimensions but describe completely different physical situations. This distinction matters in engineering calculations: joules accumulate as work is done, while newton-meters describe the rotational effect of a force at a specific moment.

Newton-Meters — The SI Standard for Torque

The Newton-meter (N·m) is the SI unit of torque, derived from the newton (SI force unit) and the meter (SI length unit). It is the standard unit for torque in automotive engineering, mechanical engineering, and scientific contexts worldwide. One N·m represents the torque produced when a one-newton force acts perpendicular to a one-meter lever arm.

Engine torque specifications in N·m are the global standard for vehicles sold outside the United States. A typical small passenger car gasoline engine might produce 150-200 N·m of maximum torque. A family sedan with a turbocharged 2-liter engine commonly achieves 300-350 N·m. Large diesel engines in commercial trucks and heavy equipment can produce 2,000-5,000 N·m or more. Electric motors are notable for producing maximum torque from zero RPM — a Tesla Model S can deliver over 600 N·m instantaneously, compared to a comparable combustion engine that only reaches peak torque within a specific RPM band.

Fastener torque specifications in automotive service manuals increasingly use N·m as the primary unit alongside lb·ft. Cylinder head bolt torque on a modern gasoline engine might be specified at 80 N·m, while wheel lug nuts typically require 100-140 N·m depending on the vehicle. Using a torque wrench calibrated in lb·ft on an N·m specification requires accurate conversion to prevent under-torquing (which can cause fastener loosening under vibration) or over-torquing (which can yield or break fasteners or strip threads).

Pound-Feet — The American Automotive Standard

Pound-feet (lb·ft), sometimes written as ft·lb or foot-pounds (though technically foot-pound can also refer to energy in the US customary system), is the torque unit dominant in American automotive engineering and service. It represents the torque produced by a one pound-force acting perpendicular to a one-foot lever arm. One pound-foot equals approximately 1.3558 N·m, so conversion between the two systems requires multiplication by this factor.

American vehicle engine specifications quote torque in lb·ft. A V8 muscle car might produce 400-450 lb·ft of torque. A diesel pickup truck might produce 900-1,000 lb·ft. These numbers sound dramatically different from their N·m equivalents (542-610 N·m for the muscle car, 1,220-1,356 N·m for the diesel truck) simply due to the different unit scale — not because American engines are "more torquey" than their European counterparts. When comparing international engine specifications, converting to a common unit is essential for accurate comparison.

Torque wrench sets in the American market are primarily calibrated in lb·ft (or its smaller sibling, lb·in for lighter fastener applications). When working from a repair manual or specification sheet that uses N·m while your torque wrench is calibrated in lb·ft, our converter provides the exact equivalent in one step.

Pound-Inches and Ounce-Inches — Small-Scale Torque

For smaller mechanical components where pound-feet would produce decimal values too small to read accurately on typical torque wrenches, pound-inches (lb·in) and ounce-inches (oz·in) provide more practical scale. One pound-inch equals 1/12 pound-foot (since 1 foot = 12 inches), which equals approximately 0.113 N·m. One ounce-inch equals 1/16 pound-inch, approximately 0.00706 N·m.

Electronic actuator torque specifications, servo motor ratings, small engine fasteners, and bicycle component torque values are commonly expressed in lb·in or oz·in. A bicycle stem bolt might be specified at 5-7 N·m (44-62 lb·in). A small computer fan motor might be rated at 10 oz·in of holding torque. RC car servos and drone motors are rated in oz·in or kg·cm. Our converter handles these small-scale torque values as precisely as the large-scale automotive values, covering the full practical range of mechanical torque measurement.

Kilogram-Force Meters — The Gravitational Metric Unit

Kilogram-force meters (kgf·m) represent torque in the gravitational metric system, where force is expressed in kilogram-force rather than newtons. One kgf·m equals 9.80665 N·m (since 1 kgf = 9.80665 N). Kilogram-force centimeters (kgf·cm) are used for smaller torque values: 1 kgf·cm = 0.0980665 N·m.

These units appear in Japanese automotive service manuals, older European technical documentation, and industrial equipment specifications from countries that have not fully transitioned to strict SI units. Many older torque wrench sets sold in Asian markets are calibrated in kgf·m. When working with vintage Japanese motorcycles, older industrial equipment specifications, or any technical document using kgf·m as the torque unit, our converter provides immediate N·m or lb·ft equivalents.

Torque in Electric Motors and Robotics

Electric motor torque rating is one of the most important specifications for motor selection in robotics, automation, electric vehicles, industrial drives, and power tools. A motor's rated torque (also called nominal or continuous torque) is the maximum torque it can deliver continuously without overheating. Peak torque is the maximum achievable for brief periods, typically 2-3 times the rated value for brush-type DC motors and up to 5-10 times for modern servo motors with appropriate drive electronics.

In robotics and servo applications, torque specifications are often given in N·m or, for smaller servos, in kg·cm. The kg·cm unit is particularly common in hobby robotics (RC servos, 3D printer stepper motor ratings) despite not being an SI unit. A standard small RC servo might be rated at 6 kg·cm (0.588 N·m), while a heavy-duty hobby servo achieves 25 kg·cm (2.45 N·m). Industrial servo motors for CNC machine axes might be rated at 10-100 N·m depending on the application. Converting between these unit systems when comparing components from different manufacturers is a routine engineering task that our converter simplifies.