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Joules to Calories Converter

Convert joules to calories and calories to joules instantly. Bidirectional energy converter with formula and common values.

Joules to Calories: 1 J equals 0.239006 cal. To convert joules to calories, multiply by 0.239006 (cal = J × 0.239006). For example, 10 J = 2.39006 cal.

4184 J = 1,000 cal

cal = J × 0.239006

How to Convert Joules to Calories

To convert from joules to calories, multiply the value by 0.239006. The conversion is linear, meaning doubling the input doubles the output.

Conversion Formula

  • Joules to Calories: cal = J × 0.239006
  • Calories to Joules: J = cal ÷ 0.239006
Joules to Calories conversion scale — a dual ruler showing 1 J equals .239 cal.
Joules to Calories conversion scale (J to cal).

Joules to Calories Conversion Chart

Joules (J)Calories (cal)
0.10.023901
0.250.059751
0.50.119503
10.239006
20.478012
30.717018
51.19503
102.39006
204.78012
255.97515
5011.9503
10023.9006
25059.7515
1000239.006

Understanding the Units

What is a Joule?

The joule is the SI derived unit of energy, equal to the work done by a force of one newton acting through a distance of one meter (1 J = 1 N·m = 1 W·s).

Named after James Prescott Joule (1818–1889), the English physicist who demonstrated the mechanical equivalent of heat.

Common contexts: physics, chemistry, engineering.

What is a Calorie?

The thermochemical calorie equals exactly 4.184 joules; the historical "small" calorie raised one gram of water by one degree Celsius.

Common contexts: chemistry, historical thermodynamics.

Real-World Reference Points

Item Joules (J) Calories (cal)
Energy to lift an apple 1 m10.239
Heart beat (resting)10.239
AA battery (alkaline)90002151.054

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FAQ

How many calories are in one joule?

One joule equals approximately 0.239006 calories (thermochemical). This means roughly 4.184 joules make up one calorie.

What is the difference between a calorie and a Calorie?

A lowercase calorie (cal) is the amount of energy needed to raise 1 gram of water by 1°C. An uppercase Calorie (Cal or kcal), used on food labels, equals 1000 small calories.

Why are joules and calories both used for energy?

Joules are the SI standard for energy used in physics and engineering. Calories remain common in nutrition and chemistry because they relate directly to heating water, which is intuitive for those fields.

How do I convert 500 joules to calories?

Multiply 500 by 0.239006. So 500 J = 119.503 cal.

How many calories are in 1 joul?

1 J equals 0.239006 cal.

How do you convert joules to calories?

Multiply the joul value by 0.239006. Formula: cal = J × 0.239006.

How many calories are in 5 joules?

5 J = 1.19503 cal.

How do you convert calories back to joules?

Use the inverse formula: J = cal ÷ 0.239006. For example, 1 cal = 4.183995 J.

What is the difference between Joul and Calory?

The joule is the SI derived unit of energy, equal to the work done by a force of one newton acting through a distance of one meter (1 J = 1 N·m = 1 W·s). The thermochemical calorie equals exactly 4.184 joules; the historical "small" calorie raised one gram of water by one degree Celsius.