Result
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Units and SI factors
All units are referenced to the SI base N (Newton).
| Unit | Name | Factor to SI | 1 unit = ? SI |
|---|
Force in engineering practice
Force is mass times acceleration, and its SI unit is the newton (N) — the force needed to accelerate one kilogram at one metre per second squared. Structural engineers more often write loads in kilonewtons (kN) or meganewtons (MN). US practice uses the pound-force (lbf), legacy metric machines use the kilogram-force (kgf), and the cgs system uses the tiny dyne.
Where each unit shows up
- N — general mechanics, spring scales and fastener tension.
- kN — structural loads, crane capacity and cable tension.
- MN — bridge piers, dam forces and large rocket thrust.
- lbf — US load ratings, fastener pull-out and thrust.
- kgf / dyn — legacy tooling specifications and cgs physics.
Conversion gotchas
Do not confuse force units with mass units: a “pound” may mean mass (lb) or force (lbf), and a “kilogram-force” is not a kilogram of mass. The exact anchor is 1 kgf = 9.80665 N (standard gravity), and 1 lbf ≈ 4.4482 N. The dyne is 10-5 N — small enough that it rarely appears outside cgs electrostatics and surface tension.
Method: every unit has a factor that maps it to its SI base. We compute value × source factor ÷ target factor, so round-trips agree to better than 1e-9.