21 kcal equals 21000 cal.
Converting kilocalories (kcal) to calories (cal) involves multiplying the value by 1000, because one kilocalorie equals one thousand calories. So, 21 kcal is 21 times 1000, resulting in 21000 cal.
Conversion Tool
Result in cal:
Conversion Formula
To convert kcal to cal, multiply the number of kilocalories by 1000. This works because 1 kcal is exactly 1000 cal. The formula is:
cal = kcal × 1000
Explanation: The calorie (cal) is a smaller unit of energy, and the kilocalorie (kcal) is 1000 times bigger. So, if you have 21 kcal, you multiply 21 by 1000.
Step-by-step:
- Start with 21 kcal
- Multiply by 1000: 21 × 1000
- = 21000 cal
Conversion Example
- Convert 5 kcal to cal:
- Take 5 kcal
- Multiply by 1000: 5 × 1000
- Result: 5000 cal
- Convert 0.75 kcal to cal:
- Take 0.75 kcal
- Multiply by 1000: 0.75 × 1000
- Result: 750 cal
- Convert 12.4 kcal to cal:
- Take 12.4 kcal
- Multiply by 1000: 12.4 × 1000
- Result: 12400 cal
- Convert 33 kcal to cal:
- Take 33 kcal
- Multiply by 1000: 33 × 1000
- Result: 33000 cal
Conversion Chart
This chart shows kcal values from -4.0 to 46.0 and their equivalent in calories. To use it, find the kcal value in the left column and read across to see the cal conversion.
| kcal | cal |
|---|---|
| -4.0 | -4000 |
| -3.0 | -3000 |
| -2.0 | -2000 |
| -1.0 | -1000 |
| 0.0 | 0 |
| 1.0 | 1000 |
| 2.0 | 2000 |
| 3.0 | 3000 |
| 4.0 | 4000 |
| 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 kilocalories?
- What is the calorie equivalent of 21 kcal?
- Convert 21 kcal to calories, what is the result?
- Is 21 kcal equal to 21000 cal or something else?
- How do you change 21 kcal into calories?
- What does 21 kcal represent in calories?
- How to calculate calories from 21 kcal?
Conversion Definitions
kcal: Kilocalorie, often called Calorie with capital C, is a unit of energy equal to 1000 small calories. It is used to measure energy content in food and physical activities. One kcal represents the energy needed to raise the temperature of 1 kilogram of water by 1 degree Celsius.
cal: The calorie is a unit of energy, smaller than the kilocalorie. It measures the amount of heat needed to raise the temperature of 1 gram of water by 1 degree Celsius. Calories are used in chemistry and physics, but in nutrition, “calorie” usually means kilocalorie.
Conversion FAQs
Why multiply kcal by 1000 to get calories?
This is because one kilocalorie (kcal) equals one thousand small calories (cal). The prefix kilo means 1000, so the conversion is direct multiplication. This unit difference makes kcal more practical when dealing with food energy, which are larger amounts.
Is 21 kcal a large amount of energy?
In dietary terms, 21 kcal is a modest amount of energy, like a small snack might provide. But in physics or chemistry, it’s a defined quantity, and can be converted easily to calories or joules. The perception of “large” depends on the context.
Can kcal values be negative, like -4 kcal in the chart?
Negative kcal values are unusual in food energy, but can exist in theoretical or experimental measurements where energy is lost or removed. The chart includes negative values just to show the conversion formula applies to all numbers, positive or negative.
Why does the tool show results with four decimal places?
The tool uses four decimal places to provide precise results even for small inputs. Though calories usually don’t require extreme precision, it helps with scientific or technical calculations where small differences matter.
Are kcal and Calorie always interchangeable?
In nutrition, kcal and Calorie (capital C) are used interchangeably, meaning 1000 small calories. However, in scientific contexts, calorie and kilocalorie are different units, so it’s important to know which unit is being used to avoid confusion.