1 calorie (cal) is equal to approximately 4.184 joules (J).
The calorie is a unit of energy commonly used in chemistry and nutrition, whereas the joule is the SI unit of energy. Converting calories to joules involves multiplying the calorie value by 4.184, because 1 calorie was originally defined as the amount of heat needed to raise the temperature of 1 gram of water by 1 degree Celsius, which corresponds to 4.184 joules.
Conversion Tool
Result in joule:
Conversion Formula
The conversion formula from calories to joules is:
Energy (J) = Energy (cal) × 4.184
This formula works because one calorie is exactly 4.184 joules. The calorie was based on heating water, while joule is based on mechanical energy units. Multiplying the calorie value by 4.184 converts it directly into joules.
Example calculation:
- Given 5 cal, to convert to joules, multiply 5 by 4.184.
- 5 cal × 4.184 = 20.92 J
- So, 5 calories is equal to 20.92 joules.
Conversion Example
- Convert 3.5 cal to joule:
- Multiply 3.5 by 4.184.
- 3.5 × 4.184 = 14.644 J.
- Result: 3.5 cal equals 14.644 joules.
- Convert 10 cal to joule:
- Multiply 10 by 4.184.
- 10 × 4.184 = 41.84 J.
- Result: 10 cal equals 41.84 joules.
- Convert 0.75 cal to joule:
- Multiply 0.75 by 4.184.
- 0.75 × 4.184 = 3.138 J.
- Result: 0.75 cal equals 3.138 joules.
- Convert 15 cal to joule:
- Multiply 15 by 4.184.
- 15 × 4.184 = 62.76 J.
- Result: 15 cal equals 62.76 joules.
Conversion Chart
| Calories (cal) | Joules (J) |
|---|---|
| -24.0 | -100.416 |
| -20.0 | -83.680 |
| -15.0 | -62.760 |
| -10.0 | -41.840 |
| -5.0 | -20.920 |
| 0.0 | 0.000 |
| 5.0 | 20.920 |
| 10.0 | 41.840 |
| 15.0 | 62.760 |
| 20.0 | 83.680 |
| 25.0 | 104.600 |
| 26.0 | 108.784 |
The chart shows calorie values in first column, and their respective joule equivalents in second. You can find the joule value by looking up the calorie amount and then reading the corresponding joule number. Negative values show energy loss or removal instead of gain.
Related Conversion Questions
- How many joules are in 1 calorie exactly?
- What is the formula to convert 1 cal to joules?
- Is 1 cal equal to 4.184 joules or more?
- How to convert 1 calorie to joules using a calculator?
- What does 1 calorie equal in joules for physics calculations?
- Can 1 cal be expressed in joules with decimals?
- Why does 1 calorie equal 4.184 joules in energy conversion?
Conversion Definitions
cal (calorie): The calorie is a unit of energy originally defined as the amount heat needed to raise the temperature of one gram of water by one degree Celsius at standard pressure. It is commonly used in food energy and chemistry, but is not an SI unit.
joule (J): The joule is the SI derived unit of energy, equal to the work done when a force of one newton moves an object one meter. It is the standard unit for energy in physics, representing mechanical, electrical, and thermal energy.
Conversion FAQs
Why is the calorie not an SI unit but the joule is?
The calorie was historically based on heating water and is convenient for food energy, but it lacks a precise mechanical definition. Joule is defined via mechanical work (force times distance) making it part of the International System of Units (SI), providing consistency across scientific disciplines.
Can the conversion factor between calorie and joule change?
The conversion factor 4.184 is fixed by international agreement and does not change. Though different definitions of calorie exist (such as thermochemical calorie), the standard calorie used in this conversion is exactly 4.184 joules.
Are all calories equal when converting to joules?
No, there are different calorie definitions like the “small calorie” (cal) and “large calorie” (kcal or Calorie). The small calorie is 4.184 joules, but the nutritional Calorie equals 1000 small calories or 4184 joules.
Is this conversion accurate for all scientific applications?
For most practical and scientific uses, multiplying by 4.184 gives accurate conversion. However, some fields may use slightly different calorie definitions for precision, but they are rare outside specialized contexts.