Kilogram-force (kgf)

CGS & old metricTraditional unit (still used in some regions)

Exactly 9.80665 newtons: the weight of one kilogram at standard gravity. Also called the kilopond; still common for torque and force in Asia and older European specs.

1 kilogram-force = 9.80665 newtons (exactly).

About the kilogram-force

Before the newton existed, engineers simply measured force by the weight of a standard mass, and the kilogram-force was that idea made official. Its alternative name, kilopond, comes from the Latin pondus, meaning weight. Its size depended on local gravity until 1901, when the General Conference on Weights and Measures adopted 9.80665 m/s2 as standard gravity, which fixed one kilogram-force at exactly 9.80665 newtons. The newton was proposed in 1913 and accepted in 1948.

A proposal to make the kilogram-force an official unit of force was rejected, and it is deprecated and outside SI. Even so it persists in niche uses: bicycle spoke tension, archery bow draw weight, bond wire strength and Vickers hardness testing. German rocket engineers of the 1940s quoted thrust in it, and Soviet and Russian space programs kept doing so until at least the late 1980s. Metric horsepower is defined from it. One kilogram-force is about 2.20462 pound-force and equals 980,665 dynes.

Sources: Wikipedia: Kilogram-force; NIST SP 811, Appendix B.8 conversion factors

Kilogram-force conversion chart

1 kilogram-force expressed in every other force unit:

More CGS & old metric units

• gram-force (force)
• dyne (force)
• tonne-force (force)
• erg (energy)
• kilogram-force meter (energy)
• erg per second (power)
• technical atmosphere (pressure)
• barye (pressure)

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