Calories ↔ kJ Calculator
Convert dietary Calories to kilojoules and kilojoules to Calories instantly. This tool is useful for comparing Australian nutrition labels with calorie-based food information and fitness apps.
Convert Food Energy
Enter an energy value, choose the source unit and select the unit you want to convert to.
Quick Calorie Conversions
Select a common dietary Calorie value.
Conversion Summary
The converter uses the standard relationship between dietary kilocalories and kilojoules.
Calories to Kilojoules Conversion Table
Common dietary Calorie values converted into kilojoules.
| Calories (kcal) | Kilojoules (kJ) | Approx. Joules |
|---|---|---|
| 50 kcal | 209.2 kJ | 209,200 J |
| 100 kcal | 418.4 kJ | 418,400 J |
| 250 kcal | 1,046 kJ | 1,046,000 J |
| 500 kcal | 2,092 kJ | 2,092,000 J |
| 1,000 kcal | 4,184 kJ | 4,184,000 J |
| 1,500 kcal | 6,276 kJ | 6,276,000 J |
| 2,000 kcal | 8,368 kJ | 8,368,000 J |
| 2,500 kcal | 10,460 kJ | 10,460,000 J |
| 3,000 kcal | 12,552 kJ | 12,552,000 J |
How to Use the Calories to kJ Calculator
Enter an energy value and choose whether the value is in dietary Calories or kilojoules. The calculator instantly converts it into the selected unit.
You can use the converter for:
- Calories to kilojoules;
- Kilojoules to Calories;
- Australian food-label comparisons;
- Fitness-app energy values;
- Meal planning; and
- Nutrition calculations.
How Do You Convert Calories to Kilojoules?
One dietary kilocalorie is equal to 4.184 kilojoules.
For example:
How Do You Convert Kilojoules to Calories?
To convert kilojoules to dietary Calories, divide the kilojoule value by 4.184.
For example:
What Is the Difference Between Calories and Kilojoules?
Calories and kilojoules are both units used to express energy.
Nutrition information in Australia commonly lists food energy in kilojoules (kJ), while many international nutrition resources, fitness apps and diet plans use Calories (kcal).
Is a Food Calorie the Same as a Scientific Calorie?
Not exactly.
In nutrition, the word Calorie with a capital C generally means one kilocalorie.
So when a food label or fitness app says 500 Calories, it usually means 500 kilocalories.
What Does kcal Mean?
kcal stands for kilocalorie.
In food and nutrition:
This converter therefore treats kcal and dietary Calories as equivalent.
What Does kJ Mean?
kJ stands for kilojoule.
One kilojoule is equal to 1,000 joules.
Why Does Australia Use Kilojoules?
Australia commonly uses kilojoules on food labels because the joule is the SI unit of energy.
This means Australian packaged-food nutrition panels often display energy as kJ even when overseas resources discuss Calories.
How Many Kilojoules Are in 100 Calories?
Therefore:
100 Calories ≈ 418 kJ.
How Many Kilojoules Are in 500 Calories?
How Many Kilojoules Are in 1,000 Calories?
How Many Kilojoules Are in 2,000 Calories?
How Many Calories Are in 1,000 kJ?
So 1,000 kJ is approximately 239 dietary Calories.
How Many Calories Are in 2,000 kJ?
How Many Calories Are in 5,000 kJ?
How Many Calories Are in 8,700 kJ?
A conversion of 8,700 kJ gives:
Calories and Kilojoules on Food Labels
Food labels can show energy per serving, per 100 grams or per 100 millilitres.
When comparing two foods, make sure you are comparing the same reference quantity.
For example, comparing one food per serving with another per 100 grams may give a misleading impression even if the energy units are correctly converted.
Calories vs Kilojoules for Weight Management
Calories and kilojoules describe the same underlying energy in different units.
Changing the unit does not change the amount of energy.
The difference is only the unit used to express it.
Calories and BMR
BMR calculators often display resting energy in Calories per day.
In Australia, the same energy can also be expressed in kilojoules.
Use the BMR Calculator to estimate resting energy expenditure.
Calories and TDEE
TDEE estimates total daily energy expenditure after taking activity into account.
For example, a TDEE of 2,500 kcal is approximately:
Use the TDEE Calculator for a personalised energy estimate based on age, height, weight and activity.
Calories and Macronutrients
Protein, carbohydrate and fat provide different amounts of dietary energy.
- Protein: approximately 4 kcal per gram;
- Carbohydrate: approximately 4 kcal per gram;
- Fat: approximately 9 kcal per gram.
Use the Macro Calculator to estimate protein, carbohydrate and fat targets.
Calories ↔ kJ Calculator Assumptions
This calculator:
- Uses 1 kcal = 4.184 kJ;
- Treats dietary Calories as kilocalories;
- Uses 1 kJ = 1,000 joules;
- Supports positive numeric energy values;
- Rounds displayed results for readability;
- Does not calculate nutritional quality;
- Does not determine individual energy needs; and
- Provides unit conversion only.
Related Health & Energy Calculators
Calories to kJ Calculator FAQs
How do I convert Calories to kilojoules?
Multiply dietary Calories by 4.184. For example, 500 kcal equals approximately 2,092 kJ.
How do I convert kilojoules to Calories?
Divide the kilojoule value by 4.184. For example, 2,000 kJ is approximately 478 kcal.
How many kJ are in 100 Calories?
100 dietary Calories equals approximately 418.4 kilojoules.
How many kJ are in 2,000 Calories?
2,000 dietary Calories equals approximately 8,368 kilojoules.
Is kcal the same as Calories?
In nutrition, one kilocalorie or kcal is commonly referred to as one dietary Calorie with a capital C.
Why do Australian food labels use kJ?
Kilojoules are commonly used in Australia because the joule is the SI unit used to measure energy.
Does converting Calories to kJ change the amount of energy?
No. Calories and kilojoules are simply different units used to express the same amount of energy.