1 calorie is equal to approximately 4.184 joules.
The calorie is a unit of energy commonly used in nutrition, while joule is the SI unit of energy. Converting from calorie to joule involves multiplying by a fixed factor, since they measure the same physical quantity but in different units.
Conversion Tool
Result in joule:
Conversion Formula
The conversion formula from calorie (cal) to joule (J) is:
Energy (J) = Energy (cal) × 4.184
This formula works because one calorie is defined as the amount of heat energy needed to raise the temperature of one gram of water by one degree Celsius, and that energy amount equals exactly 4.184 joules. Joule, being the SI unit for energy, provides a universal standard for energy measurement.
Example calculation for 1 calorie:
- Start with 1 cal
- Multiply by 4.184 (conversion factor)
- 1 cal × 4.184 = 4.184 J
Conversion Example
- Convert 5 calories to joules:
- Take 5 cal
- Multiply by 4.184
- 5 × 4.184 = 20.92 J
- Convert 0.75 calories to joules:
- Start with 0.75 cal
- Multiply by 4.184
- 0.75 × 4.184 = 3.138 J
- Convert 12.3 calories to joules:
- Take 12.3 cal
- Multiply by 4.184
- 12.3 × 4.184 = 51.4872 J
- Convert 100 calories to joules:
- Start with 100 cal
- Multiply by 4.184
- 100 × 4.184 = 418.4 J
Conversion Chart
| Calorie (cal) | Joule (J) |
|---|---|
| -24.0 | -100.4160 |
| -20.0 | -83.6800 |
| -15.0 | -62.7600 |
| -10.0 | -41.8400 |
| -5.0 | -20.9200 |
| 0.0 | 0.0000 |
| 5.0 | 20.9200 |
| 10.0 | 41.8400 |
| 15.0 | 62.7600 |
| 20.0 | 83.6800 |
| 26.0 | 108.7840 |
This chart shows calorie values in the left column and their equivalent joules in the right column. To find a joule value, locate the calorie first, then read off the joule number. Negative values represent energy loss or heat removal in joules.
Related Conversion Questions
- How many joules is 1 calorie equal to exactly?
- What is the formula to convert 1 calorie to joules?
- Is 1 calorie bigger or smaller than 1 joule?
- Can I convert 1 calorie directly to joules on a calculator?
- Why does 1 calorie equal 4.184 joules?
- How do I convert 1 calorie to joules in physics problems?
- What is the energy in joules for 1 calorie used in food?
Conversion Definitions
Calorie: A calorie is a unit of energy measuring the amount of heat needed to raise the temperature of one gram of water by one degree Celsius at standard atmospheric pressure. It is widely used in food energy measurement but is not an SI unit.
Joule: Joule is the SI unit for energy, defined as the work done when a force of one newton moves an object one meter in the direction of the force. It is used in physics and engineering as the standard unit for all forms of energy.
Conversion FAQs
Can I convert dietary calories to joules using the same factor?
Dietary calories (often written with a capital C, kilocalories) represent 1000 small calories, so you must multiply by 4184 joules per dietary calorie. The factor 4.184 applies only to small calories.
Why is the calorie not part of the SI system but the joule is?
The calorie originated as a heat measurement unit before SI was established. The joule was chosen to unify energy units across physics and engineering. SI units provide consistency for scientific calculations, so joule is preferred.
Does temperature affect the conversion between calorie and joule?
The defined calorie is based on raising water temperature at a specific condition, but the conversion factor 4.184 J per cal is fixed and does not change with temperature in practical use.
How accurate is the 4.184 joules per calorie conversion?
The value 4.184 is exact by international agreement for the thermochemical calorie. Slight variations exist in other calorie definitions, but this is the standard for scientific use.
Is it possible to convert joules back to calories?
Yes, by dividing the number of joules by 4.184, you can convert joules back to calories. This reverses the multiplication process used for calorie-to-joule conversion.