1 Calorie to Kj – Answer and Calculator Tool

1 calorie equals approximately 0.0042 kilojoules. This conversion helps understand energy measurements across different systems.

When converting 1 calorie to kilojoules, it multiplies by the conversion factor 0.004184, because 1 calorie (cal) is defined as exactly 4.184 kilojoules (kJ). This means that each calorie contains about 4.184 joules of energy, and since 1 kilojoule is 1000 joules, the result is 0.004184 kJ.

Conversion Tool

Enter value in calorie:

Result in kj:

Conversion Formula

The conversion formula from calories to kilojoules is: kj = cal * 4.184. It works because 1 calorie equals exactly 4.184 joules, and since 1 kilojoule equals 1000 joules, multiplying calories by 4.184 gives the energy in kilojoules. For example, converting 2 calories: 2 * 4.184 = 8.368 kj.

Conversion Example

• Convert 3 calories:
  • Multiply 3 by 4.184
  • 3 * 4.184 = 12.552 kj
  • This means 3 calories equals about 12.552 kilojoules.
• Convert 0.5 calories:
  • 0.5 * 4.184 = 2.092 kj
  • Half a calorie contains approximately 2.092 kilojoules.
• Convert 10 calories:
  • 10 * 4.184 = 41.84 kj
  • Ten calories convert to about 41.84 kilojoules.
• Convert -5 calories:
  • -5 * 4.184 = -20.92 kj
  • Negative calories indicate energy deficit or measurement in different context, equals about -20.92 kj.

Conversion Chart

This table shows various calorie values and their equivalent in kilojoules, from -24.0 to 26.0, increasing by 2 units. Use this to quickly find conversions for these values.

Calories	Kilojoules
-24.0	-100.416
-22.0	-92.048
-20.0	-83.68
-18.0	-75.312
-16.0	-66.944
-14.0	-58.576
-12.0	-50.208
-10.0	-41.84
-8.0	-33.472
-6.0	-25.104
-4.0	-16.736
-2.0	-8.368
0.0	0.0
2.0	8.368
4.0	16.736
6.0	25.104
8.0	33.472
10.0	41.84
12.0	50.208
14.0	58.576
16.0	66.944
18.0	75.312
20.0	83.68
22.0	92.048
24.0	100.416
26.0	108.784

Read the table by matching the calorie value on the left with its kj equivalent on the right. This helps quick reference for small or large energy measurements.

Related Conversion Questions

• How many kilojoules are in 1 calorie of energy?
• What is the kj equivalent of 1 calorie burned during exercise?
• Can I convert 1 calorie to kj for nutritional labels?
• What does 1 calorie represent in terms of energy in kj?
• How do I convert calories to kj for food calorie counts?
• Is 1 calorie the same as 1 kilojoule in energy measurement?
• How many kj are in a single calorie of food energy?

Conversion Definitions

Calorie

A calorie is a unit of energy measurement, originally defined as the heat needed to raise the temperature of 1 gram of water by 1°C. In nutrition, it often refers to a kilocalorie, which equals 1000 calories, used to quantify food energy.

Kilojoule

A kilojoule is a metric energy unit equal to 1000 joules. It measures energy transfer or work done, used widely in scientific, nutritional, and physical contexts to express energy amounts in a standardized way different from calories.

Conversion FAQs

What is the precise value of 1 calorie in kilojoules?

One calorie equals exactly 4.184 kilojoules, based on the definition of the calorie as a specific heat unit, making calculations straightforward for conversions between energy systems.

Why do nutritional labels use kilocalories instead of calories?

Because the calorie in food contexts is actually a kilocalorie, which equals 1000 calories, to simplify and avoid confusion when displaying energy content in nutrition facts.

How does the conversion factor change if I use small calories versus large calories?

The conversion factor of 4.184 applies to small calories (cal), whereas large calories (kcal) are numerically the same but are often used in dietary contexts, representing 1000 small calories.

Is the conversion from calories to kilojoules exact or approximate?

The conversion from calories to kilojoules is exact when using the defined value of 4.184 joules per calorie, ensuring precise calculations for scientific and nutritional purposes.