Convert Kilogram (kg) to Ounce (oz) instantly.
About these units
Kilogram (kg)
The kilogram is the base unit of mass in the SI system and the only SI unit defined directly by a fundamental constant rather than a physical object. Originally, its definition was tied to a platinum–iridium artifact stored in France—the famous "International Prototype Kilogram." Over time, tiny mass changes in the prototype and its official copies created difficulties for high-precision science. In 2019, the kilogram was redefined using Planck's constant, linking mass to the laws of quantum physics through the Kibble balance. This innovation ensures universality, stability, and reproducibility across the world. The kilogram is central to commerce, science, engineering, and every quantitative field dealing with matter. Its decimal relationships with other metric units (grams, milligrams, tons) make it universally convenient. From groceries to spacecraft mass budgets, the kilogram anchors modern mass measurement.
Ounce (oz)
The ounce is a unit equal to 1/16 of a pound, or approximately 28.3495 grams, with roots in ancient Roman "uncia"—one-twelfth of a pound. The ounce is used for measuring small masses in cooking, postal services, gemstones (troy ounces), and various consumer goods. Despite not being part of the metric system, the ounce remains a staple in US everyday life, from food packaging to hardware components. Its small size gives it a practical niche where grams might feel too unfamiliar for some audiences. Multiple ounce variants exist historically—avoirdupois, troy, apothecary—but the avoirdupois ounce is now the standard in general commerce. Its endurance reflects the cultural weight of imperial units and the long history of Western measurement systems.