Torque Converter
Convert torque, the twisting force on a shaft, bolt or motor, between newton meters, pound-force feet, pound-force inches, kilogram-force centimeters, ounce-force inches and other units. Pick two units, enter a value and read the result instantly.
Select two units to see the conversion factor.
This tool converts torque (force × lever arm) only. A torque in N·m is not energy in joules, so no energy units are offered. It is also not force (N) and not power (W).
Torque Formula
Torque is force multiplied by the perpendicular lever arm: τ = F × r (or F × r × sin θ at an angle). Every unit is a fixed multiple of the newton meter. Result = value × (source factor ÷ target factor). The building blocks are exact: 1 kgf = 9.80665 N, 1 gf = 0.00980665 N, 1 lbf = 0.45359237 kg × 9.80665 m/s² = 4.4482216152605 N, 1 ozf = 1/16 lbf, 1 dyne = 10⁻⁵ N, 1 ft = 0.3048 m and 1 in = 0.0254 m. So 1 lbf·ft = 12 lbf·in.
What Is Torque?
Torque is the twisting action of a force about an axis of rotation. It equals the force times the perpendicular distance from the axis to where the force acts, τ = F × r. A 100 N push on a 0.3 m wrench produces 30 N·m. The SI unit is the newton meter (N·m). Torque is what an engine delivers to a drive shaft, what a wrench applies to a bolt and what makes a motor accelerate its load, and it works with rotation speed to give power: P = τ × ω, with ω in rad/s.
Torque units combine a unit of force with a unit of length, so the list is long. Metric: N·m, N·cm, N·mm and kN·m. Gravitational metric: kgf·m, kgf·cm, kgf·mm and the gram-force units, still common on motor and servo datasheets. US customary: lbf·ft for engines and fasteners, lbf·in and ozf·in for small screws, instruments and motors, and ozf·ft. The dyne meter, dyne centimeter and dyne millimeter are small CGS units. The force in “lbf” and “kgf” is the pound-force and kilogram-force, based on standard gravity, 9.80665 m/s².
Torque is not energy. A newton meter has the same dimension as a joule, but torque is a twisting action about an axis, while energy is an amount that can be stored or transferred. One N·m of torque turning through one radian does one joule of work, but a torque of 1 N·m is not “1 joule”. For that reason this converter does not offer joules or any other energy unit. Torque is also not force (Moment of Force Converter lists the unit family for moments in statics) and not power: a motor’s power in kW or hp comes from torque and speed (kW to hp).
Supported Units
This converter supports the following 17 torque units. The last column gives the value of each unit in the base unit, the newton meter. “lbf·ft” (pound-force foot) is sometimes written “ft·lb” or “ft-lbs”; this tool uses the pound-force foot throughout.
| Unit | Symbol | Value in N·m |
|---|---|---|
| Newton meter | N·m | 1 |
| Newton centimeter | N·cm | 0.01 |
| Newton millimeter | N·mm | 0.001 |
| Kilonewton meter | kN·m | 1,000 |
| Pound-force foot | lbf·ft | 1.355817948 |
| Pound-force inch | lbf·in | 0.112984829 |
| Ounce-force foot | ozf·ft | 0.08473862177 |
| Ounce-force inch | ozf·in | 0.007061551814 |
| Kilogram-force meter | kgf·m | 9.80665 |
| Kilogram-force centimeter | kgf·cm | 0.0980665 |
| Kilogram-force millimeter | kgf·mm | 0.00980665 |
| Gram-force meter | gf·m | 0.00980665 |
| Gram-force centimeter | gf·cm | 9.80665e-5 |
| Gram-force millimeter | gf·mm | 9.80665e-6 |
| Dyne meter | dyn·m | 1e-5 |
| Dyne centimeter | dyn·cm | 1e-7 |
| Dyne millimeter | dyn·mm | 1e-8 |
How to Use the Torque Converter
- Type the torque in the value box. Decimals and scientific notation such as 0.0025 or 2.5e-3 are accepted.
- Choose the From unit and the To unit.
- The result appears instantly, or press Convert Now. Very large or very small results are shown in scientific notation.
- Use Swap Units to reverse the conversion, Copy Result to copy the answer, open Show this value in all units for a full list, and Clear to start again.
Step-by-step by hand
- Find the size of each unit in the common base unit (N·m): 1 lbf·ft = 1.355817948 N·m and 1 N·m = 1 N·m.
- Divide the source size by the target size to get the conversion factor: 1.355817948 ÷ 1 = 1.355817948, so 1 lbf·ft = 1.355817948 N·m.
- Multiply by your value: 80 lbf·ft × 1.355817948 = 108.4654359 N·m.
Torque has a direction of rotation (clockwise or counter-clockwise), so a minus sign is accepted. Zero is also valid.
Common Torque Conversions
- Wheel nut torque: 100 N·m equals 73.75621493 lbf·ft, and 80 lbf·ft equals 108.4654359 N·m.
- Small screw: 5 lbf·in equals 0.5649241451 N·m and 80 ozf·in.
- Servo motor rating: 15 kgf·cm equals 1.4709975 N·m and 208.3107989 ozf·in.
- Pound-force feet to inches: 1 lbf·ft equals 12 lbf·in.
- Small motor: 25 N·cm equals 0.25 N·m.
- Large machine: 2.5 kN·m equals 2,500 N·m and 1,843.905373 lbf·ft.
- CGS unit: 5,000,000 dyn·cm equals 0.5 N·m.
- Torque to power: an engine producing 300 N·m at 6,000 rpm delivers P = 300 × 628.3185 rad/s = 188.4955592 kW (about 252.7767087 hp).
Pound-Force Foot to Other Torque Units
Quick reference for frequently used values
| lbf·ft | N·m | lbf·in | kgf·m |
|---|---|---|---|
| 1 | 1.355817948 | 12 | 0.1382549544 |
| 5 | 6.779089742 | 60 | 0.6912747719 |
| 10 | 13.55817948 | 120 | 1.382549544 |
| 25 | 33.89544871 | 300 | 3.456373859 |
| 50 | 67.79089742 | 600 | 6.912747719 |
| 80 | 108.4654359 | 960 | 11.06039635 |
| 150 | 203.3726922 | 1,800 | 20.73824316 |
| 300 | 406.7453845 | 3,600 | 41.47648631 |
Where and Why This Conversion Is Used
- Automotive: engine and motor torque curves, wheel-nut and cylinder-head tightening specifications, which differ between regions (N·m versus lbf·ft).
- Fasteners and assembly: bolt and screw torque in N·m, lbf·ft or lbf·in, and torque wrench settings.
- Electric motors and servos: rated and stall torque, often in N·cm, kgf·cm or ozf·in.
- Industrial machinery: gearboxes, couplings and shaft sizing.
- Instrumentation: torque sensors and small precision mechanisms in mN·m, gf·cm and dyn·cm.
Limitations
- The converter changes units only. It does not compute torque from a force and a lever arm, and it does not convert torque to power or energy.
- The “pound” in lbf·ft is a unit of force, not mass. A wrench setting in lbf·ft cannot be reinterpreted using a mass.
Important Differences Between Related Measurements
- Torque vs energy: both can be written in N·m, but torque is a twisting action about an axis and energy is a scalar amount. Torque times angle in radians gives work in joules. A tightened bolt at 50 N·m is not storing 50 J of energy.
- Torque vs force: force (N) pushes or pulls in a line. Torque (N·m) twists about an axis and depends on the lever arm. A short wrench needs more force than a long one for the same torque.
- Torque vs power: power is the rate of doing work, P = τ × ω, measured in watts or horsepower. The same torque at double the speed means double the power.
- Torque vs moment of force: they share dimensions and units. Torque normally means the twisting action on a rotating or tightened part, while moment of force is the statics term for the turning effect of a force about a point.
- Torque vs moment of inertia: torque causes angular acceleration, τ = I × α. Moment of inertia (kg·m²) is the resistance, not the push.
Each converter on this site changes units within one quantity only, and none of them mixes quantities. The related tools are: Velocity - Angular, Acceleration, Acceleration - Angular, Density, Specific Volume, Moment of Inertia, Moment of Force and Torque.