Calorie to Kilojoule Converter
Convert calories to kilojoules (cal to kJ) instantly with this free online energy converter. Enter any value in the Calorie field and get the equivalent in Kilojoule immediately. This converter handles any quantity — from tiny fractions to large numbers — with full precision. No signup, no ads in the widget, and the conversion runs entirely in your browser for instant results.
The conversion factor is exact: 1 cal = 0.004184 kJ. To convert calories to kilojoules, multiply your Calorie value by 0.004184. For example, 10 cal = 0.04184 kJ. You can also reverse the calculation: 1 kJ = 239.0057361 cal.
Quick conversion table
| Calorie (cal) | Kilojoule (kJ) |
|---|---|
| 1 cal | 0.004184 kJ |
| 5 cal | 0.02092 kJ |
| 10 cal | 0.04184 kJ |
| 25 cal | 0.1046 kJ |
| 50 cal | 0.2092 kJ |
| 100 cal | 0.4184 kJ |
Use the swap button to reverse the direction, or choose a different unit from the dropdown menus to convert within the energy category.
Formula
Calorie to Kilojoule conversion: 1 cal = 0.004184 kJ kilojoules = calories × 0.004184 1 kJ = 239.0057361 cal calories = kilojoules × 239.0057361
Example
Example: Convert 10 cal to kJ: 10 cal × 0.004184 = 0.04184 kJ So, 10 cal is about 0.04184 kJ. To convert back, multiply by 239.0057361: 0.04184 kJ × 239.0057361 = 10 cal.
How to Use
- Enter the value you want to convert in the Calorie field
- The result in Kilojoule appears instantly below
- Use the dropdown menus to change units if needed
- Click 'Swap Units' to reverse the conversion direction
- Copy the result or adjust the input for a new conversion
Frequently Asked Questions
How do I convert calories to kilojoules?
Enter the value in Calorie (cal) in the 'From' field. The equivalent in Kilojoule (kJ) appears instantly in the 'To' field. The converter uses precise conversion factors and updates in real time as you type.
What is the formula to convert cal to kJ?
1 cal = 0.004184 kJ, so kilojoules = calories × 0.004184. To convert back, 1 kJ = 239.0057361 cal. The full formula and a worked example are shown on this page.
How many kilojoules are in one Calorie?
1 cal = 0.004184 kJ.
Is this Calorie to Kilojoule converter free?
Yes, completely free with no signup, no limits, and no ads in the converter widget. You can convert as many values as you need. The tool runs entirely in your browser, so your data never leaves your device.
Can I convert kilojoules back to calories?
Yes. Click the 'Swap Units' button to reverse the direction. You can also use the dropdown menus to select any other energy unit for either field.
How accurate is the cal to kJ conversion?
The converter uses high-precision conversion factors (up to 8 decimal places). Results are displayed with up to 6 decimal places, with trailing zeros removed for readability. For scientific or engineering work, always verify with official standards.