G Force Calculator

Calculate the g force acting on an object in motion using the g force calculator.

Acceleration in g0.5099 gmultiples of standard gravity — what a pilot, a rider or an accelerometer reads

Force400 N80 kg × 5 m/s²

Force in pounds-force89.9236 lbf

Force in kilograms-force40.7886 kgfthe mass that this force would weigh on Earth

Weight at this gravity784.532 N80 kg × 9.80665 m/s²

Mass80 kg176.37 lb — mass, not weight

Acceleration5 m/s²0.5099 g

Force as a fraction of weight0.5099×the same as the acceleration in g

Momentum gained per second400 kg·m/sforce is the rate of change of momentum, which is Newton's second law in its original form

The formula

F = ma; weight = mg

Mass and weight are different quantities

Mass measures how much matter there is and how strongly it resists acceleration; it is the same everywhere. Weight is the force gravity exerts on that mass, so it changes with location — the same object weighs about a sixth as much on the Moon and nothing at all in free fall, while its mass is unchanged.

The confusion is built into everyday units. A bathroom scale reads in kilograms but measures force, and a "kilogram-force" is the weight of one kilogram under standard gravity — 9.80665 newtons. Pounds are worse, serving as both a mass and a force depending on context, which is why the pound-force has its own name.

Newton originally stated the second law as force being the rate of change of momentum, which is the more general form: it still holds when mass changes, as it does for a rocket burning fuel, where F = ma alone would mislead.