Force is a push or a pull, and it is measured in newtons in the SI system. In practice you will also meet pound-force on American torque wrenches and load ratings, kilogram-force on older European equipment and gym machines, kips in structural drawings and dynes in physics textbooks. This converter switches between them using exact definitions, and shows the mass that would weigh the same under standard gravity, a quick sanity check when the numbers come from a scale or load cell.
How to use the force converter
- Enter the force in Value.
- Select its unit in From and the unit you want in To.
- The tape shows the result, the factors in both directions and the equivalent mass in kilograms and pounds.
- The table lists the force in all 13 units, from millinewtons to meganewtons.
Force conversion formula
All units are stored as newtons:
The newton is defined from Newton’s second law, F = m × a, as the force that accelerates 1 kg at 1 m/s². The “gravitational” units multiply a mass by standard gravity, gn = 9.80665 m/s²:
The poundal takes the other route: it is the force that accelerates one pound at one foot per second squared, 0.138254954376 N.
Worked example: a 100 lbf load
A winch is rated to pull 100 lbf, and the specification sheet you are comparing uses newtons:
100 lbf × 4.4482216 = 444.82 N
In kilonewtons, that is 0.4448 kN; in kilogram-force it is 45.36 kgf.
Equivalent mass: 444.82 ÷ 9.80665 = 45.36 kg, or exactly 100 lb.
The last line confirms the definition: a pound-force is precisely the weight of a one-pound mass under standard gravity.
Common force conversions
| From | To | Multiply by |
|---|---|---|
| pound-force | newtons | 4.4482216 |
| newtons | pound-force | 0.2248089 |
| kilogram-force | newtons | 9.80665 (exact) |
| kilogram-force | pound-force | 2.2046226 |
| kilonewtons | pound-force | 224.80894 |
| kips | kilonewtons | 4.4482216 |
| tonne-force | kilonewtons | 9.80665 (exact) |
| dynes | newtons | 0.00001 (exact) |
| poundals | newtons | 0.13825495 |
Where each unit is used
- Newton (N) and kilonewton (kN): SI units for physics, engineering and climbing gear. A carabiner stamped “24 kN” holds about 5,400 lbf.
- Pound-force (lbf): US mechanical specs, spring rates and thrust ratings. Aircraft engine thrust is often quoted in lbf.
- Kip: US structural and civil engineering; one kip is 1,000 lbf.
- Kilogram-force (kgf): older metric engineering and many consumer products. It is not an SI unit, but you will still see it on torque wrenches as kgf·m.
- Dyne: the CGS unit, 1 g·cm/s². It survives mainly in surface-tension values (dyn/cm).
- Tonne-force and short ton-force: press capacities and crane ratings. A “50-ton press” in the US usually means 50 short tons-force (about 445 kN).
Force, mass and weight
Mixing up mass and force is the most common source of error. A body that has a mass of 70 kg weighs about 686.5 N on Earth, 113 N on the Moon and nothing at all in orbit, yet its mass never changes. When a bathroom scale says 70 kg, it has measured a force and divided by standard gravity for you.
To calculate a force from mass and acceleration, use the force calculator. For weight on other planets, see the weight calculator. If your force acts over an area, the pressure converter handles psi, pascals and bar.
Frequently asked questions
How many newtons are in a pound-force?
One pound-force is 4.4482216152605 N, exactly by definition: it is the weight of one pound (0.45359237 kg) under standard gravity (9.80665 m/s²). One newton is about 0.2248 lbf.
What is the difference between a pound and a pound-force?
A pound (lb) is a unit of mass; a pound-force (lbf) is the force gravity exerts on that mass under standard gravity. On Earth they have the same number, which is why everyday speech uses "pound" for both.
What is a kip?
A kip is 1,000 pound-force, about 4.448 kN. Structural engineers in the US use kips for beam loads and column capacities, and ksi (kips per square inch) for stress.
How do I convert kgf to newtons?
Multiply by 9.80665. A kilogram-force is the weight of one kilogram under standard gravity, so a 50 kgf pull equals 490.33 N.