What is the SI unit of force?

The SI unit of force is the newton. Its symbol is N, and one newton is defined as one kilogram metre per second squared (1 kg·m/s²).

The unit measures how strongly an object is pushed or pulled. Newton’s second law, F = ma, connects force with mass and acceleration: applying one newton to a one-kilogram mass produces an acceleration of one metre per second squared.

The name honours English physicist Isaac Newton, whose laws of motion became central to classical mechanics. The General Conference on Weights and Measures standardized the MKS force unit in 1946 and officially adopted the name newton in 1948.

A common mix-up is confusing force with energy or power. The joule measures energy, the watt measures power, and the pascal measures pressure. Near Earth’s surface, a 200-gram apple weighs about 2 newtons.