Force & Torque Converter (N, lbf, kgf, N·m, ft·lb)
This page holds two separate converters, because force and torque are different physical quantities. Force is a push or pull. Torque, also called moment of force, is a twisting effect produced by a force acting at a distance from a pivot. They cannot be converted into each other, which is why they get their own converters here. Everything runs in your browser.
Force
Torque
Why force and torque are not interchangeable
Force is measured in newtons. Torque is measured in newton-meters, and that extra "meter" is not decoration, it is a second physical dimension.
torque = force × perpendicular distance from the pivot
The same force produces different torque depending on where it is applied. Pushing a door near the hinge takes far more force than pushing it at the handle, because the lever arm is shorter. A 100 N force at 0.1 m gives 10 N·m of torque, while the same 100 N at 0.5 m gives 50 N·m.
This is why there is no conversion factor from newtons to newton-meters. Asking how many newton-meters a newton is, is like asking how many square meters a meter is: the question is missing a dimension.
Force units
The newton is the SI unit, defined as the force that accelerates one kilogram at one meter per second squared. On Earth, a 1 kg mass experiences about 9.81 N of gravitational force, which is why a bathroom scale showing "70 kg" is really measuring roughly 687 N and dividing by standard gravity.
Kilogram-force (kgf) takes exactly that shortcut and makes it a unit: 1 kgf is the weight of 1 kg under standard gravity, so 9.80665 N. It is not an SI unit but survives in older machinery specifications and some torque wrenches.
Pound-force (lbf) is its imperial equivalent, the weight of one pound under standard gravity, which is 4.4482216 N.
| From | Newtons | Kilonewtons | kgf | lbf |
|---|---|---|---|---|
| 1 N | 1 | 0.001 | 0.101972 | 0.224809 |
| 1 kN | 1000 | 1 | 101.972 | 224.809 |
| 1 kgf | 9.80665 | 0.009807 | 1 | 2.20462 |
| 1 lbf | 4.44822 | 0.004448 | 0.453592 | 1 |
| 1 dyne | 0.00001 | 10-8 | 0.00000102 | 0.00000225 |
Torque units
Torque units always name a force and a length together. The SI unit is the newton-meter (N·m). Imperial practice uses foot-pounds (ft·lb) for larger values and inch-pounds (in·lb) for smaller ones, with exactly 12 in·lb per ft·lb.
| From | N·m | kgf·m | ft·lb | in·lb |
|---|---|---|---|---|
| 1 N·m | 1 | 0.101972 | 0.737562 | 8.85075 |
| 1 kgf·m | 9.80665 | 1 | 7.23301 | 86.7962 |
| 1 ft·lb | 1.35582 | 0.138255 | 1 | 12 |
| 1 in·lb | 0.112985 | 0.011521 | 0.083333 | 1 |
A note on notation: torque is written N·m while energy is written J (joule), even though a joule is dimensionally also a newton-meter. The convention keeps them visually distinct because they describe different things, torque is a rotational effect, energy is work done.
Practical examples
Tightening bolts
Fastener specifications are given in N·m in Europe and ft·lb or in·lb in the US. Typical values: a spark plug takes 25 ft·lb (33.9 N·m), a car wheel nut 80 to 120 N·m (59 to 89 ft·lb), and small electronics screws well under 1 N·m. Both under-tightening and over-tightening cause failures, so converting correctly matters, particularly for wheel nuts and engine components.
Engine torque figures
Car specifications quote torque alongside power. A typical family car produces 200 to 300 N·m (148 to 221 ft·lb). Torque describes pulling force at a given engine speed, power describes the rate of work, and the two are linked by rotational speed. This is why a diesel with high torque at low RPM feels strong from a standstill even when its peak power is modest.
Structural loads
Construction specifies loads in kilonewtons. A 1000 kg load exerts about 9.81 kN. Older documentation sometimes uses "tonnes-force", where 1 tf is 9.80665 kN, which is a frequent source of confusion when comparing old and new drawings.
Torque wrench conversion
When following a manual written in different units from your wrench, convert before you start rather than estimating. Multiplying ft·lb by 1.356 gives N·m. For inch-pound wrenches used on smaller fasteners, remember that in·lb values are twelve times the ft·lb figure, an easy factor to lose track of and a common cause of stripped threads.
Frequently asked questions
Can I convert newtons directly to newton-meters?
No. Force and torque are different quantities. Torque depends on both the force and the distance from the pivot, so there is no single conversion factor. You would need to know the lever arm length.
What is kilogram-force?
The force gravity exerts on a 1 kg mass under standard conditions, equal to 9.80665 N. It is a non-SI unit still found in older specifications and some torque wrenches.
How many newton-meters is a foot-pound?
1.35582 N·m. In the other direction, 1 N·m is 0.737562 ft·lb.
How many inch-pounds are in a foot-pound?
Exactly 12, since a foot contains 12 inches and the force component is unchanged.
Why is torque written in N·m when a joule is also a newton-meter?
Dimensionally they are the same, but they describe different physical concepts. Torque is a rotational effect, energy is work performed. Keeping N·m for torque and J for energy prevents them being mistakenly added together or treated as equivalent.
How much force does a 70 kg person exert on the ground?
About 687 N (70 × 9.80665). Bathroom scales display the mass in kilograms rather than this force, having already divided by standard gravity.
Related converters
- Weight and mass converter, for the mass behind a gravitational force
- Pressure converter, for force distributed over an area
- Power converter, for the power figures quoted alongside engine torque
- All unit converters