Imported groceries or European product labels often list energy only in kJ (kilojoules), leaving it unclear how many calories that actually is.
The exact formula
One kcal is 4.184 kJ. Multiply kcal by 4.184 to get kJ.
A quick mental-math shortcut
"kJ ≈ kcal × 4.2" is close enough for most purposes. Going the other way, "kcal ≈ kJ ÷ 4.2".
Reading overseas nutrition labels
EU nutrition labels standardly list kJ first with kcal in parentheses. Korean and US labels usually show only kcal (or Cal), so to read an overseas product's energy in familiar calories, divide the kJ figure by 4.184.
Energy burn units in fitness apps
Some fitness devices and apps — cycling power meters especially — report energy burned in kJ. Converting to kcal keeps comparisons across different apps consistent.
Conversion table
| kcal | kJ |
|---|---|
| 100 | 418 |
| 200 | 837 |
| 500 | 2092 |
| 2000 (daily reference) | 8368 |
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