1 calorie equals approximately 0.004184 kilojoules.
To convert calories to kilojoules, multiply the number of calories by 0.004184 because 1 calorie is defined as exactly 4.184 kilojoules. This means if you have a certain calorie amount, you just scale it by this factor to get the energy in kilojoules, which is a metric unit of energy measurement.
Calorie to Kilojoule Conversion
Result in kj:
Conversion Formula
The conversion formula from calories to kilojoules is: Kj = Calories × 4.184. This works because one calorie, specifically the small calorie, equals exactly 4.184 kilojoules. By multiplying the calorie value by 4.184, you get the energy in kilojoules, which is the SI unit of energy. For example, converting 1 calorie: 1 × 4.184 = 4.184 kj.
Conversion Example
- Converting 5 calories:
- Multiply 5 by 4.184
- 5 × 4.184 = 20.92 kj
- Converting 10 calories:
- 10 × 4.184 = 41.84 kj
- Converting 0.5 calories:
- 0.5 × 4.184 = 2.092 kj
- Converting 2.5 calories:
- 2.5 × 4.184 = 10.46 kj
Conversion Chart
This chart shows some calories and their equivalent in kilojoules, from -24.0 to 26.0 calories. Use it to quickly find the energy in kj for specific calorie values or to compare different amounts easily.
| Calories | Kilojoules (kj) |
|---|---|
| -24.0 | -0.1003 |
| -20.0 | -0.0837 |
| -16.0 | -0.0670 |
| -12.0 | -0.0504 |
| -8.0 | -0.0337 |
| -4.0 | -0.0170 |
| 0.0 | 0.0 |
| 4.0 | 0.0167 |
| 8.0 | 0.0334 |
| 12.0 | 0.0501 |
| 16.0 | 0.0668 |
| 20.0 | 0.0835 |
| 24.0 | 0.1002 |
| 26.0 | 0.1086 |
Use this chart to quickly see how many kilojoules correspond to various calorie amounts, by reading across the row for a specific calorie number.
Related Conversion Questions
- How many kilojoules are in 1 calorie of energy?
- What is the conversion rate from calories to kilojoules?
- If I consume 1 calorie, how much energy is that in kj?
- How do you convert calories to kilojoules manually?
- What is the kilojoule equivalent of 1 calorie in food energy?
- Can I convert calories to kj using a calculator?
- What is the formula to turn calories into kilojoules?
Conversion Definitions
Calorie
A calorie is a unit measuring energy, often used in nutrition to quantify the energy food provides. It is defined as the amount of energy needed to raise 1 gram of water by 1 degree Celsius, with the small calorie equal to 4.184 joules.
Kilojoule
A kilojoule (kj) is a metric energy unit equal to 1,000 joules. It is used worldwide to measure energy in scientific, nutritional, and mechanical contexts, representing the amount of work done or heat transferred in energy calculations.
Conversion FAQs
Why is 1 calorie equal to 4.184 kj?
This is because the small calorie, used in scientific contexts, is defined precisely as 4.184 joules. When converting to kilojoules, multiply by 4.184, making 1 calorie equal to 4.184 kj.
How precise is converting calories to kj in cooking recipes?
Conversion accuracy depends on whether you use the small calorie or dietary calorie; most nutritional calculations use dietary calories where 1 kcal equals 4.184 kj. Small calorie conversions are more precise but less common in food contexts.
Can I convert calories to kj with an online calculator?
Yes, many online conversion tools and calculators allow you to input calories and receive kilojoules instantly, based on the standard conversion factor of 4.184.
Is there a difference between small calories and dietary calories in conversions?
Yes, small calories (cal) are used in scientific contexts, while dietary calories (kcal) are used in nutrition. Both are often equated in conversions, but the precise value for dietary calories is 4.184 kj per kcal.