Joules to Calories Converter
Enter the energy in joules below to convert it to calories.
Convert Joules to Calories
Enter a value in joules (J) to convert to calories (cal).
Joule to Gram Calorie Conversion Table
Table showing various joule measurements converted to calories. Click any preset value or arrow to load it into the converter.
| Joules (J) | Calories (cal) |
|---|---|
| 1 J | 0.2390057 cal |
| 2 J | 0.4780115 cal |
| 5 J | 1.1950287 cal |
| 10 J | 2.3900574 cal |
| 15 J | 3.585086 cal |
| 20 J | 4.7801147 cal |
| 25 J | 5.9751434 cal |
| 30 J | 7.1701721 cal |
| 50 J | 11.9502868 cal |
| 75 J | 17.9254302 cal |
How to Convert Joules to Calories
To convert joules to calories, multiply the energy by the following conversion ratio: 0.2390057 calories/joule.
Since one joule is equal to 0.2390057 calories, you can use this simple formula to convert:
The energy in calories is equal to the energy in joules multiplied by 0.2390057.
For example, here's how to convert 100 joules to calories using the formula above.
How Many Calories Are in a Joule?
There are 0.2390057 calories in a joule, which is why we use this value in the formula above.
Our joule to gram calorie calculator automatically converts your energy measurements with full decimal and scientific precision across US customary, imperial, and SI metric standards.
Joules and calories are both units used to measure energy. Keep reading to learn more about each unit.
What Is a Joule?
Coherent SI unit of energy and work (1 W·s = 1 N·m). It serves as a primary reference unit for measuring energy across scientific and practical applications. [1]
The joule is classified as an International System of Units (SI) unit of energy. Joules can be abbreviated as J; for example, 1 joule can be written as 1 J.
As the primary coherent reference unit for energy in this category, all other energy units are mathematically anchored to the joule (J).
In practice, joules (J) are widely used across standard energy applications within International System of Units (SI) workflows, engineering documentation, and technical data sheets.
What Is a Gram Calorie?
A gram calorie is a unit of energy equal to 4.184 joules (J), the base unit for energy. Thermochemical gram calorie defined as 4.184 Joules. [2]
The gram calorie is classified as a standard unit of energy. Calories can be abbreviated as cal; for example, 1 gram calorie can be written as 1 cal.
When working with calories (cal) in formulas or technical specifications, always verify whether your target system uses SI metric, US customary, or British imperial standards.
In practice, calories (cal) are widely used across standard energy applications within international standard workflows, engineering documentation, and technical data sheets.
When converting energy between joules (J) and calories (cal), keep full floating-point precision (1 J = 0.2390057 cal; 1 cal = 4.184 J) during intermediate calculations and round only the final gram calorie figure to match your instrument tolerance.
More Joule & Gram Calorie Conversions
Need to calculate in the opposite direction? Use our calories to joules converter (cal to J) to switch your starting unit immediately. You can also explore related tools such as converting joules to kilojoules, converting joules to foot-pounds, or converting kilojoules to joules.
Frequently Asked Questions
References
- [1]NIST CODATA StandardNIST CODATA (CODATA Energy & Thermodynamic Constants)·Energy Metrology Standard — Joules (J) to Calories (cal)
- [2]NIST SP 811 SpecificationNIST SP 811 (NIST SP 811 App. B.9 (Energy, Work & Heat))·Unit Specifications: Joule (J) & Gram Calorie (cal) (cal)
- [3]BIPM ReferenceBIPM (Derived SI Unit: Joule (J))·Conversion Factors & Mathematical Basis (J to cal)