Reading a food label
A 250-calorie snack is about 1,046 kJ on an Australian label.
Use Calories to Kilojoules
Converts calories (kcal) to kilojoules in this tab, with nothing sent anywhere.
Runs entirely on your deviceThe conversion happens in this browser tab. Nothing you type is uploaded, logged or stored, which is worth knowing for anything you would not paste into a search box.
A snack listed as 250 food calories converts to roughly 1,046 kJ, which makes an overseas nutrition label easier to compare. Here, calorie means the dietary kilocalorie printed as Calorie with a capital C.
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Browse all general convertersAbout Calories to Kilojoules
Food energy is labelled in two units: calories (strictly kilocalories, or kcal) in the US, UK and much of the world, and kilojoules (kJ) in Australia, New Zealand and the EU alongside calories. Converting calories to kilojoules is what you do to read a label in kcal against a diet or app that works in kilojoules. One kcal is about 4.184 kJ. Nutrition is where the two units collide most: Australian and European labels lead with kilojoules, and a calorie-counting app set to kJ needs the conversion. The kilojoule is the strict scientific unit of energy, while the food calorie is a historical unit that stuck - which is why 'calories' on a label are really kilocalories, a thousand of the physics calorie. Sports nutrition, dietitian plans and fitness trackers move between the two depending on the country and the app, so anyone comparing an American label against an Australian one converts. Because one calorie is about 4.2 kilojoules, a quick estimate multiplies calories by roughly 4.2. Check whether a nutrition entry means kcal or small physics calories before comparing its kilojoule value.
Using Calories to Kilojoules
- Type a number of kcal. You can paste a value with its unit; the tool reads the number.
- The exact factor is applied and the result is shown as kJ, updating live as you type.
- Copy the answer, or switch to the reverse converter to go from kJ back to kcal.
Where calories to kilojoules helps
Both directions
Need the opposite? The kJ-to-kcal converter is linked below and uses the exact inverse factor.
Before you use the result
- The result is rounded for readability; the underlying factor is exact, so a value converted and back may differ in the last decimal place.
- Units in your input are ignored - only the number is read - so make sure the figure you type is really in kcal.
Questions about Calories to Kilojoules
How many kilojoules in a calorie?
About 4.184 kJ per food calorie (kcal). So a 100-calorie item is roughly 418 kJ.
Is my data uploaded?
No. Calories to Kilojoules does the arithmetic in this browser tab; the value is calculated on your device and is not sent to a server.
Related tools
Kilojoules to Calories
Convert kilojoules to calories for food labels, recipes, and fitness apps. See kJ to kcal examples and calculate locally in your browser.