Force
Newtons, lbf, kgf, dyne
About This Calculator
Force is a vector quantity that causes a mass to accelerate, measured in newtons (SI), pound-force (imperial), kilogram-force (metric engineering), or dynes (CGS). Newton's second law relates force, mass, and acceleration: F = ma. Understanding force units is essential in physics, engineering, and structural analysis.
Formula
1 newton (N) = 1 kg·m/s²
1 pound-force (lbf) = 4.44822 N
1 kilogram-force (kgf) = 9.80665 N (weight of 1 kg at standard gravity)
1 dyne = 0.00001 N = 10⁻⁵ N (CGS unit)
Example Calculation
Convert 100 pounds-force to newtons and kilogram-force.
- N = 100 × 4.44822 = 444.82 N
- kgf = 444.82 / 9.80665 = 45.36 kgf
100 lbf = 444.82 N = 45.36 kgf
Force Unit Conversions
| Unit | Newtons (N) | lbf | kgf | dyne |
|---|---|---|---|---|
| 1 N | 1 | 0.22481 | 0.10197 | 100,000 |
| 1 lbf | 4.44822 | 1 | 0.45359 | 444,822 |
| 1 kgf | 9.80665 | 2.20462 | 1 | 980,665 |
| 1 dyne | 0.00001 | 0.000002248 | 0.000001020 | 1 |
Frequently Asked Questions
What is the difference between mass and force?
Mass is an intrinsic property of matter (measured in kg or lbs mass); force is mass multiplied by acceleration. Weight is the gravitational force on an object: W = m × g where g = 9.80665 m/s². A 1 kg mass weighs about 9.81 N (or 1 kgf) on Earth's surface.
What is a kilogram-force?
A kilogram-force (kgf) is the force exerted by 1 kilogram of mass under standard Earth gravity. 1 kgf = 9.80665 N. It is a metric engineering unit that is convenient because the numerical value equals the weight in kilograms — a 70 kg person exerts 70 kgf of force on a scale.
Why is the newton named after Newton?
Isaac Newton formulated the laws of motion and universal gravitation. The SI unit of force was named in his honor. One newton is defined as the force needed to accelerate a 1 kg mass at 1 m/s² — a direct application of his second law F = ma.
What is a dyne?
The dyne is the CGS (centimeter-gram-second) unit of force, equal to 10⁻⁵ N. While mostly replaced by the newton in modern science, dynes still appear in surface tension measurements (dynes per centimeter = mN/m) and older physics literature.