Torque Converter
Convert torque — the moment of force — between newton metres, pound-feet, pound-inches, kilogram-force metres and kilogram-force centimetres. Torque is a rotational effect: a force applied at a distance from a pivot, so its units are always a force times a length. It is what a wrench applies to a bolt and what an engine delivers to a driveshaft. The conversions here are exact, derived from the defined pound-force and standard gravity.
How to use this tool
- Enter a torque value.
- Choose the unit you are converting from.
- Choose the unit you want the answer in.
- Read the result, or show every equivalent unit at once.
- For fastener specs, watch whether a figure is pound-feet or pound-inches — they differ by a factor of twelve.
The formula
Torque, or moment of force, is force applied at a distance from a pivot. Its SI base unit is the newton metre. Imperial pound-feet and metric kilogram-force metres are fixed multiples derived from the pound-force and standard gravity.
torque = force × lever_arm
base_N·m = value × (N·m per unit)- N·m
- Newton metre, SI unit of torque
- lb·ft
- Pound-force foot, 1.35582 N·m
- kgf·m
- Kilogram-force metre, 9.80665 N·m
A newton metre and a joule have the same base units but are not interchangeable: torque is a rotational quantity, energy a scalar.
Worked examples
Wheel nut
- Given
- 120 N·m
- Result
- ≈ 88.5 lb·ft
A typical car wheel-nut torque of 120 newton metres is about 88 pound-feet.
Small fastener
- Given
- 25 lb·in
- Result
- ≈ 2.82 N·m
Pound-inches suit small fasteners; 25 lb·in is under 3 N·m.
Metric spec
- Given
- 5 kgf·m
- Result
- ≈ 49 N·m
Older metric specs use kilogram-force metres; 5 kgf·m is about 49 N·m via standard gravity.
Frequently asked questions
They differ by a factor of twelve, since a foot is twelve inches. One pound-foot equals twelve pound-inches. Small fasteners are often specified in pound-inches to avoid awkward fractions, so mixing the two up over-torques a bolt twelvefold.
They share the same base units but are not interchangeable. A joule is energy — force applied over a distance in the direction of motion. A newton metre of torque is force applied at a perpendicular distance about an axis. Torque is not conventionally expressed in joules for this reason.
It is a torque of one kilogram-force acting at one metre. A kilogram-force is the weight of one kilogram under standard gravity, so 1 kgf·m equals 9.80665 N·m. It appears on older metric machinery and some torque specs.
Torque is the twisting force at an instant; power is the rate of doing work, combining torque with rotational speed. An engine can have high torque at low revs but modest power, or vice versa. They are related by power = torque × angular speed.
Torque controls the clamping force in a joint. Too little and the joint can loosen or leak; too much can stretch or snap the bolt or crush the parts. That is why manufacturers specify exact torque values, and why converting them accurately between units matters.
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