Calories to Kilocalories
Type a value in either box to convert between calories and kilocalories. The factor is 0.001.
| Calories | Kilocalories |
|---|---|
| 1 cal | 0.001 kcal |
| 2 cal | 0.002 kcal |
| 3 cal | 0.003 kcal |
| 5 cal | 0.005 kcal |
| 10 cal | 0.01 kcal |
| 25 cal | 0.025 kcal |
| 50 cal | 0.05 kcal |
| 100 cal | 0.1 kcal |
How to use
- Enter a value in the Calories field.
- The Kilocalories figure appears immediately — no button to press.
- Typing in the Kilocalories field converts back to Calories the same way.
- Use the reference table for the values that come up most often.
Calories to Kilocalories formula
Converting calories to kilocalories is a single multiplication by 0.001.
kcal = cal × 0.001
Put another way, one calorie is exactly 1/1,000 of a kilocalorie.
Why this factor: the calorie and the kilocalorie are both defined against the joule, so dividing one definition by the other gives 0.001 directly. Both definitions are set out in full below.
To go the other way, divide by 0.001 — or use the Kilocalories to Calories converter, which is the same calculation reversed.
Worked example
Start with 500 cal. Multiply by 0.001 to get 0.5 kcal.
500 cal × 0.001 = 0.5 kcal
The converter above does this for any value you type, in either direction.
What is a calorie?
A calorie is the energy needed to warm one gram of water by one degree Celsius.
Definition: The thermochemical calorie is defined as exactly 4.184 joules.
Where it is used: Chemistry and physics literature, and older engineering references.
Worth knowing: The 'calories' on a nutrition label are actually kilocalories — 1,000 of these. A 500-Calorie meal is 500 kcal, or about 2.1 million joules.
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.
Calories vs Kilocalories
The calorie and the kilocalorie belong to the same family of units, so converting between them is usually a matter of shifting a decimal point or applying a small whole-number factor.
Frequently asked questions
How many kilocalories are in a calorie?
One calorie equals 0.001 kilocalories.
What is the formula to convert calories to kilocalories?
Multiply the number of calories by 0.001. To reverse it, divide by 0.001 instead.
How do I convert kilocalories back to calories?
Divide by 0.001, which is the same as multiplying by 1000.
How many kilocalories are in 10 calories?
10 cal works out to 0.01 kcal.
Is there anything to watch out for with calories?
The 'calories' on a nutrition label are actually kilocalories — 1,000 of these. A 500-Calorie meal is 500 kcal, or about 2.1 million joules.
How is the calorie defined?
The thermochemical calorie is defined as exactly 4.184 joules.