Unit Converter

Convert From Joules to Calories and Vice Versa

Joules ↔ Calories

Type in either joules or calories — it’ll convert to the other automatically!


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🔋 What is a Joule (J)?

A joule is the **SI unit of energy**, defined as the work done when a force of one newton moves an object one meter. It’s widely used in **physics**, **engineering**, and **electricity**, and is also used to express **food energy** in many countries.

🍽️ What is a Calorie (cal)?

A calorie is a **metric unit of energy** used commonly in **nutrition** and **heat energy**. Technically, one calorie is the amount of energy needed to raise 1 gram of water by 1°C. The “calorie” used on food labels is actually a kilocalorie (kcal).

🧠 Quick Comparison

Unit Equivalent Used In
1 joule 0.239006 cal Physics, electricity, global standard
1 calorie (cal) 4.184 joules Nutrition, food science, thermodynamics

🧮 How to Convert

Joules to Calories:
cal = joules × 0.239006

Calories to Joules:
joules = cal × 4.184

🧪 Example:

500 J × 0.239006 ≈ 119.50 cal

💡 Quick Tip

Multiply calories (food) by 4184 to get **joules**. For example, a 100-calorie snack = 418,400 joules of energy!

🎉 Did You Know?

The term “calorie” comes from the Latin *calor*, meaning “heat.” While the SI unit is the joule, many countries still use **calories on nutrition labels** because they’re easier to relate to.

🔥 Real-World Energy Examples

  • 1 cal – Heating 1g of water by 1°C
  • 4.2 kJ – 1 kilocalorie (food calorie)
  • 2000 kcal – Average daily adult intake ≈ 8.4 million joules
  • 100 J – Energy to lift an apple one meter 10 times

📊 Joules to Calories Conversion Chart

Joules (J) Calories (cal)
10.239
102.39
10023.90
500119.50
1000239.01
50001195.03

📜 Timeline: Joules vs Calories

  • 1840s: “Calorie” introduced in thermodynamics
  • 1870s: Joule becomes SI unit of energy
  • Modern use: Joules dominate physics, calories remain popular in nutrition

🌐 When to Use Joules vs Calories

  • 💡 Joules: Physics, work, electricity, global standard
  • 🍫 Calories: Food energy, exercise, nutritional science
  • 🧮 Quick Tip: Multiply J × 0.239 to estimate cal

🎯 Interactive Converter

500 J = 119.50 cal