Battery Equivalents and Replacements

kJ to cal: Kilojoules (kJ) to Calories (cal) Conversion Calculator and Table

Kilojoules and calories are units of energy, and their conversions are simple and straightforward - one just has to remember that "k" stands for "kilo," which is, according to the SI prefixes table, 103 (one thousand) of the main value and that calorie is tied to the energy required to increase or decrease the temperature of water.

Published: January 10, 2024.

To convert kilojoules to calories, write the value in kilojoules and click 'Calculate':

Kilojoules (kJ) to Calories (cal)

Kilojoules (kJ):

Calories (cal):

To convert calories to kilojoules, check our Calories (cal) to Kilojoules (kJ) Conversion Calculator and Table article.

How To Convert Kilojoules (kJ) to Calories (cal)

"k" stands for "kilo" and means "one thousand."  Thus, one kilojoule equals 1000 joules:

1kJ = 1000J

Also, there are "two" types of calories which describe energy, these are:

  • Small calorie (cal): energy required to increase 1 gram (1g) of water by 1°C at normal/standard conditions (room temperature (20°C), 1 atmosphere pressure). Small calorie (cal) is also known as thermochemical calorie.
  • Large calorie (Cal): energy required to increase 1 kilogram (1 kg) of water by 1°C at normal/standard conditions (room temperature (20°C), 1 atmosphere pressure). Large calorie (Cal) is known as "food calorie."

The relation between small calorie (cal) and large calorie (Cal) is:

1 Cal = 1000 cal = 1 kcal

Unless otherwise noted, whenever discussing calories, we are discussing/talking about small calories (cal).

The relationship between small calories and kilojoules is as follows:

1 cal = 4.184 J = 0.004184 kJ

1 kJ = 1/0.004184 cal = ~239.0057361376 cal = ~239 cal

For example, if You want to convert 15.34 kJ to cal, You can write:

E(kJ) = 15.34 kJ = 15.34 / 0.004184 cal = 3666.348 cal = 3.666348 kcal = 3.666348 Cal

Similarly, 1500 kJ to cal:

(EkJ) = 1500 kJ = 1500 / 0.004184 cal = 358508.6 cal = 358.5086 kcal = 358.5086 Cal


Kilojoules (kJ) to Calories (cal) Conversion Table

The following chart contains the most common Kilojoules (kJ) values converted to calories (cal):

Kilojoules (kJ) Calories (cal)
0.01 2.390
0.1 23.90
0.25 59.75
0.5 119.5
1 239.0
2 478.0
3 717.0
5 1195.0
10 2390.0
50 11950
100 23900


If You wish to convert values that are not in the table, please use the kilojoules to calories conversion calculator.

What are Joules?

The joule, a unit of energy in the International System of Units (SI), plays a very important role in various scientific and engineering disciplines. Defined as the energy transferred to an object when a force of one newton acts on it over a distance of one meter, the joule is a fundamental unit that bridges concepts in physics, engineering, and beyond.

Historically, the joule is named after James Prescott Joule, an English physicist active in the 19th century.

Joule's experiments in the domain of heat and mechanical work laid the groundwork for the first law of thermodynamics and significantly contributed to the development of the concept of energy conservation.

His determination of the mechanical equivalent of heat, which quantifies the amount of mechanical work needed to produce an equivalent amount of heat, was a landmark discovery, leading to the establishment of the joule as a standard unit of energy.

In practical terms, the joule finds its application across a wide spectrum. In everyday life, it is commonly used to express the amount of energy consumed or required by various appliances and activities.

In scientific contexts, the joule is essential for expressing quantities in mechanics, electricity, and thermal physics, among other fields.

Understanding the joule is crucial for professionals in science and engineering, as it provides a common language for discussing energy in its various forms.

From the kinetic energy of moving objects to the potential energy stored in compressed springs or elevated objects, the joule serves as a versatile and indispensable unit in the quantification of energy.

What are Calories?

The calorie, a unit of energy, is widely used in various contexts, particularly in nutrition and physics. Defined as the amount of heat energy needed to raise the temperature of one gram of water by one degree Celsius, the calorie is a unit that bridges the gap between food energy and physical energy measurements.

Historically, the concept of the calorie emerged in the 19th century, primarily through the work of Nicolas Clément, a French physicist. It was initially a tool in the field of chemistry and physics to measure energy, particularly in heat transfer. However, with the growing interest in human metabolism and nutrition science, the calorie gained prominence in the field of dietetics and became a household term.

In the realm of nutrition, the term "calorie" often refers to what is scientifically known as a kilocalorie (kcal), or 1,000 small calories. This larger unit, commonly called the food calorie, is denoted with a capital 'C' (Cal) to distinguish it from the smaller calorie (cal). The food Calorie (Cal) is the standard unit used on food labels in many countries, including the United States, and represents the amount of energy required to fuel the body's metabolic processes.

The distinction between the small calorie (cal) and the food Calorie (Cal) is very important in both scientific and everyday contexts. While the small calorie is used in physics and chemistry to measure tiny amounts of energy, the food Calorie is relevant in dietary and nutritional settings, where larger energy quantities are more practical for discussion. This differentiation helps avoid confusion and ensures accurate communication, especially in dietary planning and food energy content analysis.

Understanding calories is essential for professionals in nutrition, health, and fitness, as well as for individuals managing their dietary intake.

The calorie, in both its small and large forms, provides a fundamental metric for energy exchange in the body and in various physical processes, making it a key concept in both science and everyday life.