In physics, a derived SI unit, the **newton** (symbol: N) is the unit of force, named for Sir Isaac Newton in recognition of his work on classical mechanics. It was adopted by the General Conference on Weights and Measures (CGPM) in 1960. It is defined as the amount of force required to accelerate a one-kilogram mass at a rate of one meter per second per second.

Its dimensions in SI base units are m·kg·s^{-2}.

It is also the unit of weight, as weight is the force acting between two objects due to gravity. A mass of one kilogram near the Earth's surface has a weight of approximately 9.81 newtons, although this figure varies by a few tenths of one percent over the Earth's surface. Conversely, an object with a mass of 102 grams weighs roughly one newton. Rather fittingly, given the story about Newton's discovery of gravity, this is about the mass of a small apple.

See also: dyne, the unit of force of the (mostly obsolete) CGS system