Joules to Kilojoules Converter

To convert a measurement in joules to kilojoules, multiply the value by 0.001. The conversion factor comes from the relationship between both units and the joule.

For example, to convert 5 J to kilojoules: 5 × 0.001 = 0.005 kJ.

A joule is the SI derived unit of energy, equal to the work done when a force of one newton moves an object one meter (1 N·m). Named after the English physicist James Prescott Joule, who established the mechanical equivalent of heat in the 1840s. The joule became the SI standard for all forms of energy, work, and heat.

Common uses of joules include: Scientific and engineering energy calculations; Nutrition labeling in metric countries; Mechanical work and kinetic energy; Electrical energy in physics (watt-seconds).

A kilojoule equals 1,000 joules and is the standard metric unit for expressing food energy on nutrition labels in most of the world. As metric countries adopted SI units for food labeling, the kilojoule replaced the food calorie on packaging in regions such as Australia, New Zealand, and the European Union (shown alongside kcal).

Common uses of kilojoules include: Food energy on nutrition labels; Dietary and exercise energy tracking; Chemical reaction energy (enthalpy); Battery and mechanical energy specs.

Here are some common values converted:

1 J = 0.001 kJ 5 J = 0.005 kJ 10 J = 0.01 kJ 50 J = 0.05 kJ 100 J = 0.1 kJ