Calories to Gigajoules Converter
Enter the energy in calories below to convert it to gigajoules.
Convert Calories to Gigajoules
Enter a value in calories (cal) to convert to gigajoules (GJ).
Gram Calorie to Gigajoule Conversion Table
Table showing various gram calorie measurements converted to gigajoules. Click any preset value or arrow to load it into the converter.
| Calories (cal) | Gigajoules (GJ) |
|---|---|
| 1 cal | 4.184e-9 GJ |
| 10 cal | 0.000000042 GJ |
| 100 cal | 0.000000418 GJ |
| 1,000 cal | 0.000004184 GJ |
| 10,000 cal | 0.00004184 GJ |
| 100,000 cal | 0.0004184 GJ |
| 1,000,000 cal | 0.004184 GJ |
| 5,000,000 cal | 0.02092 GJ |
| 10,000,000 cal | 0.04184 GJ |
| 25,400,000 cal | 0.1062736 GJ |
How to Convert Calories to Gigajoules
To convert calories to gigajoules, multiply the energy by the following conversion ratio: 4.184e-9 gigajoules/gram calorie.
Since one gram calorie is equal to 4.184e-9 gigajoules, you can use this simple formula to convert:
The energy in gigajoules is equal to the energy in calories multiplied by 4.184e-9.
For example, here's how to convert 5 calories to gigajoules using the formula above.
How Many Gigajoules Are in a Gram Calorie?
There are 4.184e-9 gigajoules in a gram calorie, which is why we use this value in the formula above.
Our gram calorie to gigajoule calculator automatically converts your energy measurements with full decimal and scientific precision across US customary, imperial, and SI metric standards.
Calories and gigajoules are both units used to measure energy. Keep reading to learn more about each unit.
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. [1]
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.
What Is a Gigajoule?
A gigajoule is a unit of energy equal to 1,000,000,000 joules (J), the base unit for energy. Equal to 1,000,000,000 Joules, common in natural gas billing. [2]
The gigajoule is classified as an International System of Units (SI) unit of energy. Gigajoules can be abbreviated as GJ; for example, 1 gigajoule can be written as 1 GJ.
In the metric system, "giga" is the standard SI prefix for billions, or 10⁹. This makes the gigajoule (GJ) a convenient decimal multiple of the joule (J).
In practice, gigajoules (GJ) are widely used across large-scale industrial, bulk, and macro-level energy specifications within International System of Units (SI) workflows, engineering documentation, and technical data sheets.
When converting energy between calories (cal) and gigajoules (GJ), keep full floating-point precision (1 cal = 4.184e-9 GJ; 1 GJ = 239,005,736.1376673 cal) during intermediate calculations and round only the final gigajoule figure to match your instrument tolerance.
More Gram Calorie & Gigajoule Conversions
Need to calculate in the opposite direction? Use our gigajoules to calories calculator to switch your starting unit immediately. You can also explore related tools such as converting gigajoules to calories, converting calories to joules, or converting calories to kilocalories.
Convert from Calories
Frequently Asked Questions
References
- [1]NIST CODATA StandardNIST CODATA (CODATA Energy & Thermodynamic Constants)·Energy Metrology Standard — Calories (cal) to Gigajoules (GJ)
- [2]NIST SP 811 SpecificationNIST SP 811 (NIST SP 811 App. B.9 (Energy, Work & Heat))·Unit Specifications: Gram Calorie (cal) (cal) & Gigajoule (GJ)
- [3]BIPM ReferenceBIPM (Derived SI Unit: Joule (J))·Conversion Factors & Mathematical Basis (cal to GJ)