21 kcal is equal to 21000 cal.
This conversion is done by multiplying the kilocalorie value by 1000 because 1 kilocalorie (kcal) is exactly 1000 calories (cal). So, 21 kcal multiplied by 1000 gives you the value in calories.
Conversion Tool
Result in cal:
Conversion Formula
The formula to convert kilocalories (kcal) to calories (cal) is:
cal = kcal × 1000
This works because 1 kcal represents 1000 calories, which is a standard unit relationship in energy measurement. The kilocalorie is simply a larger unit, so to find the equivalent number of smaller calories, you multiply by 1000.
For example, converting 21 kcal:
- Multiply 21 by 1000.
- 21 × 1000 = 21000 cal.
- Therefore, 21 kcal equals 21000 cal.
Conversion Example
- 15 kcal to cal:
- Multiply 15 by 1000.
- 15 × 1000 = 15000 cal.
- So, 15 kcal is 15000 cal.
- 0.5 kcal to cal:
- Multiply 0.5 by 1000.
- 0.5 × 1000 = 500 cal.
- Thus, 0.5 kcal equals 500 cal.
- 100 kcal to cal:
- Multiply 100 by 1000.
- 100 × 1000 = 100000 cal.
- Hence, 100 kcal is 100000 cal.
- 3.75 kcal to cal:
- Multiply 3.75 by 1000.
- 3.75 × 1000 = 3750 cal.
- Therefore, 3.75 kcal equals 3750 cal.
Conversion Chart
The below table shows values from -4.0 to 46.0 kcal converted to calories. To use it, find the kcal value in the left column and see its equivalent cal value on the right. Negative values represent energy loss or deficit, positive values represent energy gain.
| kcal | cal |
|---|---|
| -4.0 | -4000 |
| -3.0 | -3000 |
| -2.0 | -2000 |
| -1.0 | -1000 |
| 0.0 | 0 |
| 1.0 | 1000 |
| 5.0 | 5000 |
| 10.0 | 10000 |
| 15.0 | 15000 |
| 20.0 | 20000 |
| 25.0 | 25000 |
| 30.0 | 30000 |
| 35.0 | 35000 |
| 40.0 | 40000 |
| 45.0 | 45000 |
| 46.0 | 46000 |
Related Conversion Questions
- How many calories are in 21 kcal exactly?
- What is 21 kilocalories converted into calories?
- If I have 21 kcal, how much is that in cal?
- Can you convert 21 kcal to cal with a formula?
- Why does 21 kcal equal 21000 calories?
- Is 21 kcal the same as 21000 cal or different?
- How to calculate calories from 21 kilocalories by hand?
Conversion Definitions
kcal: Kilocalorie, often called a large calorie, measures energy in food and fuel. It equals 1000 small calories and is used to express the energy content in nutrition labels. One kcal is the energy needed to raise 1 kilogram of water by 1 degree Celsius.
cal: The calorie, sometimes called a small calorie, is a unit of energy defined as the amount needed to raise 1 gram of water by 1 degree Celsius. It is smaller than a kilocalorie and used less in food energy contexts, but important in physics and chemistry.
Conversion FAQs
Why multiply kcal by 1000 to get cal?
Because 1 kilocalorie equals 1000 calories. The prefix “kilo-” means thousand, so to convert from the larger unit (kcal) to the smaller unit (cal), you multiply by 1000. This is a direct unit scale conversion, no complex calculation needed.
Can kcal values be negative?
Yes, kcal values can be negative in contexts like energy balance where energy is lost or consumed. Negative kcal means energy deficit, which translates directly to negative calories when converted by multiplying by 1000.
Are kcal and Cal the same?
In food labeling, “Cal” with uppercase C equals kilocalorie (kcal), not calorie. So 1 Cal = 1 kcal = 1000 cal. It’s a common source of confusion but uppercase “Cal” represents the larger unit, not the small calorie.
Why do nutrition labels use kcal instead of cal?
Because calorie content in food is very large, using kcal makes numbers manageable and easier to read. Listing calories in cal would make numbers large and cumbersome, so kcal is a convenient unit in nutrition.
Is the kcal to cal conversion exact?
Yes, it is exact by definition. 1 kcal always equals 1000 cal. The relationship is fixed and does not involve rounding or estimation.