Megajoules to Kilocalories
An instant megajoules-to-kilocalories converter, with the formula and a reference table below.
| Megajoules | Kilocalories |
|---|---|
| 1 MJ | 239.005736 kcal |
| 2 MJ | 478.011472 kcal |
| 3 MJ | 717.017208 kcal |
| 5 MJ | 1195.028681 kcal |
| 10 MJ | 2390.057361 kcal |
| 25 MJ | 5975.143403 kcal |
| 50 MJ | 11950.286807 kcal |
| 100 MJ | 23900.573614 kcal |
How to use
- Enter a value in the Megajoules field.
- The Kilocalories figure appears immediately — no button to press.
- Typing in the Kilocalories field converts back to Megajoules the same way.
- Use the reference table for the values that come up most often.
Megajoules to Kilocalories formula
Converting megajoules to kilocalories is a single multiplication by 239.005736.
kcal = MJ × 239.005736
Why this factor: the megajoule and the kilocalorie are both defined against the joule, so dividing one definition by the other gives 239.005736 directly. Both definitions are set out in full below.
To go the other way, divide by 239.005736 — or use the Kilocalories to Megajoules converter, which is the same calculation reversed.
Worked example
Take 2000 MJ and multiply by the factor 239.005736: the result is 478011.472275 kcal.
2000 MJ × 239.005736 = 478011.472275 kcal
The converter above does this for any value you type, in either direction.
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.
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.
Megajoules vs Kilocalories
The megajoule is a metric unit while the kilocalorie is a specialized 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 kilocalories are in a megajoule?
One megajoule equals 239.005736 kilocalories.
What is the formula to convert megajoules to kilocalories?
Multiply the number of megajoules by 239.005736. To reverse it, divide by 239.005736 instead.
How do I convert kilocalories back to megajoules?
Divide by 239.005736, which is the same as multiplying by 0.004184.
How many kilocalories are in 10 megajoules?
10 MJ works out to 2390.057361 kcal.
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 megajoule defined?
Exactly 1×10⁶ joules. One kilowatt-hour is exactly 3.6 MJ.