The deprecated unit kilogram-force (kgf) or kilopond (kp) is the force exerted by one kilogram of mass in standard Earth gravity (defined as exactly 9.806 65 m/s²). One kilogram-force is equal to exactly 9.806 65 newtons.

The kilogram-force has never been a part of the International System of Units (SI), which was introduced in 1960. The SI unit of force is the newton.

Grams-force and kilograms force were never well-defined units until the CGPM adopted a standard acceleration of gravity of 980.665 cm/s² for this purpose in 1901, though they had been used in low-precision measurements of force before that time.

External link

http://www1.bipm.org/en/si/si_brochure/chapter2/2-2/2-2-2.html