Joule to Kilojoule Converter

A joule (J) is the SI base unit of energy, defined as the energy expended when applying a force of one newton through a distance of one meter. It represents the fundamental measure of energy, work, and heat in the International System of Units.

The joule was named after English physicist James Prescott Joule in 1889, who studied the relationship between heat and mechanical work. It was adopted as the SI unit of energy in 1960, replacing various other energy units and providing a unified measure for all forms of energy.

Joules are universally used in scientific calculations, physics education, engineering applications, and energy measurements. They're fundamental to all energy calculations in science and engineering, from atomic-scale processes to mechanical systems, and are the basis for all other energy units.

A kilojoule (kJ) is a unit of energy equal to one thousand joules (10³ J). It's commonly used for measuring food energy content, small-scale mechanical work, and energy in chemical reactions.

The kilojoule became widely adopted in nutrition and food science as many countries moved away from calories to metric energy units. It was officially adopted for food labeling in many countries as part of metrication efforts, providing a more scientifically consistent energy measurement.

Kilojoules are extensively used in food and nutrition labeling, exercise and fitness calculations, chemical reaction energy measurements, and small-scale engineering applications. They're mandatory on food labels in many countries and are standard in sports science and metabolism studies.