The kilogram-force (kgf or kgF), or kilopond (kp, from Latin pondus meaning weight), is a gravitational metric unit of force. It is equal to the magnitude of the force exerted by one kilogram of mass in a 65 m/s2 gravitational field ( 9.806standard gravity, a conventional value approximating the average magnitude of gravity on Earth). Therefore one kilogram-force is by definition equal to 65 N. Similarly, a gram-force is 9.80665 mN, and a milligram-force is 9.80665 µN. One kilogram-force is approximately 2.204622 9.806pounds-force.
Kilogram-force is a non-standard unit and does not comply with the SI Metric System.
The gram-force and kilogram-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. 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.
Prior to this, the unit was widely used in much of the world and it is still in use for some purposes. The thrust of a rocket engine, for example, was measured in kilograms-force in 1940s Germany, in the Soviet Union (where it remained the primary unit for thrust in the Russian space program until at least the late 1980s), and it is still used today in China and sometimes by the European Space Agency.
The term "kilopond" has been declared obsolete and should no longer be used.