In physics, mass is a measure of an object’s inertia – the resistance of an object to a change in its speed when a force is applied to it. This definition may seem foreign to our intuitive understanding of mass, because we generally associate mass with weight.

Mass and weight are related but distinctly separate phenomena. Where mass is completely independent of its location, weight is a force dependent on both mass and gravity (i.e. Weight = Mass × Gravity). These terms are often incorrectly used interchangeably because on the surface of earth the gravity we experience is almost the same everywhere. Therefore, weight and mass seem to be directly proportional to each other.

For a more information on mass, inertia and weight, see Britannica.com.

Use our free online mass unit conversion calculator to easily convert between units of mass including grams (g), kilograms (kg), metric tonnes (tonne), short tons (shton), long tons (Lton), pounds (lb) and ounces (oz).

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