Convert g to kg

Gram

Definition

A gram (symbol: g) is an SI unit of mass equal to one-thousandth of a kilogram, the SI’s base mass unit. Since 2019, the kilogram—and therefore the gram—is rooted in the fixed numerical value of Planck’s constant, ensuring a stable, artifact-free definition.

Origins

The term “gram” comes from the Late Latin gramma, itself borrowed from Greek, meaning “small weight.” Originally, in the late 18th century, one gram was based on the mass of one cubic centimetre of pure water at 4 °C. As the SI evolved, the gram was simply redefined to maintain its exact ratio to the kilogram (0.001 kg).

Modern Use

Grams are everywhere: in kitchens (measuring spices and ingredients), on nutrition labels (values per 100 g), in laboratories (precise chemical quantities), and retail packaging around the globe.

Kilogram

Definition

A kilogram (symbol: kg) is the SI’s fundamental unit of mass. As of May 20 2019, its value is fixed by assigning Planck’s constant the exact value of 6.62607015 × 10⁻³⁴ J·s, with the metre and second defined via the speed of light and cesium-133 frequency. This modern definition guarantees the kilogram’s consistency worldwide.

Origins

The word “kilogram” derives from the French kilogramme, combining Greek kilo- (“thousand”) with Latin gramma (“small weight”). Initially tied to the mass of one litre of water at freezing point, the kilogram later relied on a platinum-iridium cylinder stored near Paris. Tiny drifts in that prototype’s mass led to the 2019 shift to a constants-based definition.

Modern Use

Kilograms underpin virtually all mass measurements—in industry, science, trade, and daily life—throughout the world. In many countries, it is the default for groceries, shipping, and personal weight, even where other systems persist.

Gram → Kilogram Conversion Table

How to Convert

• 1 g = 0.001 kg

• 1 kg = 1000 g

Example

Convert 15 g to kilograms: