kJ to Calories Calculator

Convert kilojoules (kJ) to calories (kcal) and vice versa. Perfect for reading nutrition labels and planning your diet.

Energy Calculator:

Convert between kilojoules, kilocalories, and calories. Understand nutrition labels and calculate your daily energy intake.

kJ to Calories Converter

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Conversion Results

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to convert between kJ and calories

kJ to Calories Converter

If you've ever looked at a nutrition label, you've probably noticed energy listed in kilojoules (kJ) or calories (kcal). Some countries use kJ, while others prefer calories. The good news is that converting between them is straightforward once you know the formula.

The Core Conversion Formula

The relationship between kilojoules and calories is constant:

Main Conversion
1 kilocalorie (kcal) = 4.184 kilojoules (kJ)
*This is the standard conversion factor

From this, we get:

kJ to Calories
Calories (kcal) = kJ ÷ 4.184
Calories to kJ
kJ = kcal × 4.184
Small Calories Note
1 kcal = 1000 cal
*Food "calories" are actually kilocalories

Worked Example

Let's say a snack contains 836 kJ of energy.

To convert to calories:
Calories = 836 ÷ 4.184
Calories ≈ 200 kcal

So, 836 kJ equals about 200 kcal.

Energy From Macronutrients

Energy in food comes from macronutrients:

4
kcal/g
Protein
4
kcal/g
Carbs
9
kcal/g
Fat

kJ to Calories Conversion Table

Here's a reference table showing common energy conversions:

Energy (kJ) Energy (kcal) Small cal
100 kJ 23.9 kcal 23,900 cal
200 kJ 47.8 kcal 47,800 cal
418 kJ 100 kcal 100,000 cal
500 kJ 119.5 kcal 119,500 cal
836 kJ 200 kcal 200,000 cal
1000 kJ 239 kcal 239,000 cal
1255 kJ 300 kcal 300,000 cal
1500 kJ 358.5 kcal 358,500 cal
1674 kJ 400 kcal 400,000 cal
2000 kJ 478 kcal 478,000 cal
2092 kJ 500 kcal 500,000 cal
2500 kJ 597.5 kcal 597,500 cal
3000 kJ 717 kcal 717,000 cal
4000 kJ 956 kcal 956,000 cal
5000 kJ 1195 kcal 1,195,000 cal
6000 kJ 1434 kcal 1,434,000 cal
7000 kJ 1673 kcal 1,673,000 cal
8368 kJ 2000 kcal 2,000,000 cal
10000 kJ 2390 kcal 2,390,000 cal
12552 kJ 3000 kcal 3,000,000 cal
Quick Tip:

Whether you're reading nutrition labels, planning meals, or studying science, converting kJ to calories is a simple mathematical process. With the right formula and automatic unit conversion, you can switch between energy units instantly and accurately.