Kilocalories to Megajoules
Convert kilocalories to megajoules instantly — one kilocalorie is 0.004184 megajoules.
| Kilocalories | Megajoules |
|---|---|
| 1 kcal | 0.004184 MJ |
| 2 kcal | 0.008368 MJ |
| 3 kcal | 0.012552 MJ |
| 5 kcal | 0.02092 MJ |
| 10 kcal | 0.04184 MJ |
| 25 kcal | 0.1046 MJ |
| 50 kcal | 0.2092 MJ |
| 100 kcal | 0.4184 MJ |
How to use
- Enter a value in the Kilocalories field.
- The Megajoules figure appears immediately — no button to press.
- Typing in the Megajoules field converts back to Kilocalories the same way.
- Use the reference table for the values that come up most often.
Kilocalories to Megajoules formula
The factor from kilocalories to megajoules is 0.004184.
MJ = kcal × 0.004184
Why this factor: the kilocalorie and the megajoule are both defined against the joule, so dividing one definition by the other gives 0.004184 directly. Both definitions are set out in full below.
To go the other way, divide by 0.004184 — or use the Megajoules to Kilocalories converter, which is the same calculation reversed.
Worked example
Given 500 kcal, multiplying by 0.004184 yields 2.092 MJ.
500 kcal × 0.004184 = 2.092 MJ
The converter above does this for any value you type, in either direction.
What is a kilocalorie?
A kilocalorie is 1,000 calories, and is what food labeling calls a 'Calorie'.
Definition: Exactly 4,184 joules.
Where it is used: Nutrition and dietary energy in the US and much of the world, and metabolic measurements.
Worth knowing: Written with a capital C ('Calorie') or as 'kcal' on labels. This is the unit meant by everyday talk about counting calories.
What is a megajoule?
A megajoule is one million joules, used for substantial energy quantities.
Definition: Exactly 1×10⁶ joules. One kilowatt-hour is exactly 3.6 MJ.
Where it is used: Fuel energy content, natural gas billing, and industrial energy accounting.
Kilocalories vs Megajoules
The kilocalorie is a specialized unit while the megajoule is a metric unit. That is why the factor between them is not a round number: the two systems were defined independently and only later tied together by exact agreement.
Frequently asked questions
How many megajoules are in a kilocalorie?
One kilocalorie equals 0.004184 megajoules.
What is the formula to convert kilocalories to megajoules?
Multiply the number of kilocalories by 0.004184. To reverse it, divide by 0.004184 instead.
How do I convert megajoules back to kilocalories?
Divide by 0.004184, which is the same as multiplying by 239.005736.
How many megajoules are in 10 kilocalories?
10 kcal works out to 0.04184 MJ.
Is there anything to watch out for with kilocalories?
Written with a capital C ('Calorie') or as 'kcal' on labels. This is the unit meant by everyday talk about counting calories.
How is the kilocalorie defined?
Exactly 4,184 joules.