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Torque Converter

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About This Tool

Torque Converter: Convert Between All Torque Units

The Torque Converter is a free online tool that instantly converts torque values between 8 units spanning SI, imperial, and gravitational measurement systems. Whether you need to compare an engine torque figure specified in pound-feet to a Newton-meter rating, verify a fastener torque spec given in pound-inches, look up a motor holding torque in ounce-inches, or translate an older kg·m value to modern N·m, this tool delivers high-precision results in real time with configurable decimal places.

All conversions are performed client-side using Newton-meter (N·m) as the normalized base unit. Enter a value in any supported unit and every other unit updates simultaneously — no button press required. Enable the "Show all unit conversions" option to display a grouped reference table across all three unit categories, making it easy to compare values side by side.

Supported Torque Units

The converter covers 8 units grouped into three practical categories.

SI Units

  • Newton-meter (N·m) — The coherent SI unit of torque, defined as the moment produced by one Newton of force acting perpendicular to a one-meter moment arm. Named after Isaac Newton and the meter, it is the universal reference for all modern engineering and scientific torque specifications worldwide, and serves as the base unit through which all other conversions in this tool are normalized.
  • Kilonewton-meter (kN·m) — Equal to 1,000 N·m. Used for large-scale structural and civil engineering applications such as bridge girder connections, building column base moments, wind turbine shaft torque, and heavy industrial gearboxes. A wind turbine main shaft, for instance, may transmit several thousand kN·m of torque at rated power.
  • Newton-centimeter (N·cm) — Equal to 0.01 N·m. Used for small electric motors, robotic joints, precision actuators, medical devices, and laboratory instrumentation where torques are too small to express conveniently in full Newton-meters. A typical hobby servo motor might deliver 3–6 N·cm of torque at its rated voltage.

Imperial / US Customary Units

  • Pound-foot (lb·ft) — The torque produced by a force of one pound-force acting at a perpendicular distance of one foot, equal to approximately 1.3558 N·m. The dominant torque unit for automotive engine ratings, vehicle wheel-nut torque specifications, and industrial machinery in North America. Engine torque curves in US market vehicles are invariably quoted in lb·ft, making this unit essential for automotive engineers and enthusiasts working across metric and US markets.
  • Pound-inch (lb·in) — Equal to one-twelfth of a pound-foot (approximately 0.1130 N·m). Used for smaller torques such as those in instrument panel fasteners, small gear assemblies, electronic enclosure screws, and precision mechanical components. Many US-market torque wrenches for electrical work and PCB assembly are calibrated in lb·in.
  • Ounce-inch (oz·in) — Equal to one-sixteenth of a pound-inch (approximately 0.007062 N·m). The standard torque unit for stepper motors, servo motors, and brushless motors used in 3D printers, CNC routers, robotic arms, drone actuators, and hobby electronics. A NEMA 17 stepper motor used in desktop 3D printers is typically rated at 40–60 oz·in of holding torque.

Gravitational / Mechanical Units

  • Kilogram-meter (kg·m) — A gravitational unit equal to 9.80665 N·m, representing the torque produced by one kilogram-force at one meter radius. Widely used in older European, Japanese, and Soviet engineering standards and still encountered in legacy machinery documentation, older automotive service manuals, and some industrial equipment specifications. Converting kg·m to N·m requires multiplying by the standard gravitational acceleration (g = 9.80665 m/s²).
  • Gram-centimeter (g·cm) — Equal to approximately 0.0000981 N·m. An extremely small torque unit used in micro-motor specifications, watch and clock mechanism design, precision instrument engineering, and miniature servo datasheets. It represents the moment produced by one gram-force at one centimeter radius — useful when torques in N·m or even N·cm would be expressed as inconveniently small decimal fractions.

How Torque Conversion Works

Every conversion is normalized through Newton-meters in two steps. First, the input value is multiplied by the conversion factor of the source unit to obtain the equivalent torque in N·m. Then that N·m value is divided by the conversion factor of the target unit to produce the final result. This two-step approach ensures consistent accuracy for any pair of units without requiring a dedicated formula for every possible combination.

As an example, converting 300 lb·ft to Newton-meters:

  • 300 lb·ft × 1.35581795 N·m/lb·ft = 406.745 N·m
  • 406.745 N·m ÷ 1 N·m/N·m = 406.745 N·m

And converting 406.745 N·m back to oz·in:

  • 406.745 N·m ÷ 0.00706155 N·m/oz·in = 57,600 oz·in

For values involving very large or very small conversion factors — such as gram-centimeters (1 g·cm = 9.807 × 10⁻⁵ N·m) — the tool automatically switches to scientific notation to keep results readable and unambiguous.

Key Torque Reference Values

  • 1 N·m = 0.7376 lb·ft = 8.8507 lb·in = 141.61 oz·in = 0.1020 kg·m
  • 1 lb·ft = 1.3558 N·m = 12 lb·in = 192 oz·in = 0.1383 kg·m
  • 1 lb·in = 0.1130 N·m = 16 oz·in = 0.08333 lb·ft
  • 1 oz·in = 0.007062 N·m = 0.0625 lb·in = 0.005208 lb·ft
  • 1 kg·m = 9.80665 N·m = 7.233 lb·ft = 86.80 lb·in
  • 1 kN·m = 1,000 N·m = 737.56 lb·ft = 8,850.7 lb·in

Practical Applications of Torque Conversion

Torque measurement spans a wide range of scales and engineering disciplines. Here are common scenarios where unit conversion is essential:

  • Automotive Engineering and Service: Engine torque figures are reported in N·m in European and Asian markets and in lb·ft in North America. A turbocharged engine producing 400 N·m delivers approximately 295 lb·ft. When servicing imported vehicles, following manufacturer torque specifications for cylinder head bolts, wheel nuts, and drivetrain fasteners in the correct unit is critical for safety and reliability. This converter instantly bridges the two systems.
  • Robotics and Motion Control: Motor and servo datasheets from different manufacturers use a mix of units — oz·in for North American hobby components, N·cm or N·m for European industrial servos, and kg·cm (a variant of the gravitational system) for Asian servo brands. Robotics engineers frequently need to compare motors rated in different units to select the correct actuator for a given payload and speed requirement.
  • Structural and Civil Engineering: Connection design in steel structures involves bolt preload torques and moment demands at joints measured in kN·m or lb·ft depending on the code used (Eurocode vs. AISC). International engineering teams working on cross-border infrastructure projects convert between these systems routinely.
  • Industrial Machinery and Gearboxes: Gearbox and motor specifications from European manufacturers (N·m) must often be compared with those from US suppliers (lb·ft) when selecting replacements or upgrades. A gearbox rated at 500 N·m output and one rated at 370 lb·ft are essentially equivalent (500 N·m ≈ 368.8 lb·ft), which this tool confirms in seconds.
  • 3D Printing and CNC Machining: Stepper and servo motors for desktop fabrication machines are nearly always specified in oz·in in North America, while European equivalents are rated in N·cm or mN·m. Comparing motor choices across these specifications requires accurate unit conversion to ensure the selected motor can overcome the load torque of the drive mechanism.
  • Legacy Equipment Documentation: Older machinery manuals — from Japanese industrial equipment to Soviet-era machine tools — often specify torque in kg·m or kg·cm. Converting these values to modern N·m units is necessary when sourcing replacement fasteners, setting torque wrenches, or verifying that updated components meet the original design intent.

Tips for Using the Torque Converter

  • Enable "Show all unit conversions" to display every supported unit simultaneously, grouped by category. This is ideal for cross-referencing values — for example, seeing at a glance how a 200 N·m torque reads in lb·ft, lb·in, oz·in, and kg·m all at once.
  • Increase the decimal places setting when working with oz·in or g·cm conversions where the N·m values are very small. The tool will automatically use scientific notation when a result falls below 0.0001 or exceeds one trillion.
  • Use the Swap button to immediately reverse a conversion — for example, converting lb·ft to N·m and then swapping to verify the round-trip result matches the original input.
  • The conversion history panel records your last 10 conversions during the session. Click any history entry to restore those values as the current input, making it easy to compare multiple related torque specifications in sequence.
  • Note that torque (N·m) and energy (also N·m = Joules) share the same dimensional unit but represent different physical quantities. Torque is a rotational moment; energy is work done. This converter handles torque only. Use the Energy Converter for joule-based energy calculations.

Frequently Asked Questions

Is the Torque Converter free?

Yes, Torque Converter is totally free :)

Can I use the Torque Converter offline?

Yes, you can install the webapp as PWA.

Is it safe to use Torque Converter?

Yes, any data related to Torque Converter only stored in your browser (if storage required). You can simply clear browser cache to clear all the stored data. We do not store any data on server.

What torque units does this converter support?

The Torque Converter supports 8 units across three groups: SI (N·m, kN·m, N·cm), Imperial (lb·ft, lb·in, oz·in), and Mechanical (kg·m, g·cm). All conversions use Newton-meter (N·m) as the normalized base unit for maximum accuracy.

What is the difference between pound-foot and pound-inch?

Pound-foot (lb·ft) and pound-inch (lb·in) both express torque in US customary units but differ by a factor of 12, since 1 lb·ft = 12 lb·in. Pound-foot is the standard unit for automotive engine and fastener torque specifications in North America, while pound-inch is used for smaller torques such as those found in instrument panels, small motors, and precision hardware. In SI terms, 1 lb·ft ≈ 1.3558 N·m and 1 lb·in ≈ 0.1130 N·m.

Why is N·m used as the base unit for torque conversion?

The Newton-meter (N·m) is the coherent SI unit of torque, defined as the moment produced by one Newton of force acting at a perpendicular distance of one meter from the axis of rotation. Using N·m as the intermediate base unit ensures all conversions remain consistent with international standards. Every other unit is converted to N·m first, then to the target unit — this two-step approach avoids rounding errors from chained conversions.

What is the ounce-inch and where is it used?

The ounce-inch (oz·in) is the torque produced by one ounce-force acting at one inch radius. It equals approximately 0.007062 N·m. This unit is common in stepper motor, servo motor, and brushless motor specifications for hobby robotics, 3D printers, CNC machines, and small industrial actuators. A NEMA 17 stepper motor, for example, might be rated at 40–50 oz·in of holding torque.

How does kilogram-meter (kg·m) relate to Newton-meter?

The kilogram-meter (kg·m) is a gravitational unit of torque equal to the moment produced by one kilogram-force at one meter radius. Since one kilogram-force equals 9.80665 N (standard gravitational acceleration), 1 kg·m = 9.80665 N·m. This unit was widely used in older European and Soviet engineering standards but has largely been superseded by N·m in modern practice.

What is the maximum torque value this tool can handle?

The converter accepts torque values up to 1 × 10¹² N·m equivalent. This upper limit covers virtually all practical engineering scenarios — from micro-motor torques in the µN·m range up to the torque output of the world's largest industrial turbines and marine propulsion systems. Values exceeding this limit are unlikely to arise in real-world applications, and the tool will display an error if the limit is exceeded.