What this conversion means in practice
You already have values in Kilocalorie (IT) (kcal) and need Kilojoule (kJ) for the same material, drawing, or dataset. The factor below is the exact reciprocal of the forward direction; use it when sources quote the “other” unit first.
Nutrition panels often give kilocalories while exercise hardware and international meal databases quote kilojoules. Converting kcal → kJ lets you align a restaurant label with a training app that expects metric energy without reworking the whole diary.
The IT calorie definitions used here match the main energy converter, so you can cross-check against other pages on the site without wrestling with thermochemical variants.
Rough check: one kcal is a bit more than 4 kJ; if your answer is off by tenfold, you probably multiplied where you should divide.
The key relationship on this page is 1 kcal = 4.1868 kJ. Use it for quick sanity checks: if the magnitude looks wrong, confirm you are using the same calorie or torque convention as your data source.
How to convert kilocalorie (it) to kilojoule
Multiply the kilocalorie (it) value by 4.1868 to get kilojoule (same factors as the full energy converter, normalized through joules).
Example: 100 kcal × 4.1868 = 418.679999999993 kJ
Food “Calories” are kilocalories: the left column should use those kcal values, not small calories.
Kilocalorie (IT)
Definition: The kilocalorie (IT) is one thousand IT gram-calories; it is the unit behind the word “Calorie” on most nutrition panels.
History and origin: Grew from calorimetry and steam-table work; the IT variant ties heat measurements to a specific water-heating reference.
Current use: Nutrition, dietetics, and exercise energy budgets; also appears in some industrial heat-balance discussions when kcal remains customary.
Kilojoule
Definition: One kilojoule is one thousand joules, a convenient SI multiple for energies larger than everyday joule counts.
History and origin: Arrived with SI prefixes to keep numbers readable as industrial and electrical systems handled larger energy flows.
Current use: Common on food labels outside the US, in exercise metrics, and in technical summaries where kJ is easier to scan than long joule strings.
Kilocalorie (IT) to Kilojoule conversion table
| Kilocalorie (IT) (kcal) | Kilojoule (kJ) |
|---|---|
| 1 kcal | 4.1868 kJ |
| 10 kcal | 41.867999999999 kJ |
| 50 kcal | 209.339999999996 kJ |
| 100 kcal | 418.679999999993 kJ |
| 250 kcal | 1,046.699999999982 kJ |
| 420 kcal | 1,758.45599999997 kJ |
| 1,000 kcal | 4,186.799999999929 kJ |
| 2,000 kcal | 8,373.599999999858 kJ |
Kilocalorie (IT) to Kilojoule FAQ
Quick answers for Kilocalorie (IT)-to-Kilojoule rounding (reverse workflow), precision, and common mistakes.
How many kilojoules are in one kilocalorie?
Using the IT factors in this tool, 1 kcal ≈ 4.1868 kJ. Multiply kcal by that ratio to get kJ.
Why does my gym display kJ but my diet app uses kcal?
Different regions standardize labels differently. Convert between them with one consistent definition (here, IT) so totals stay comparable.
Is this the same kJ as chemistry class?
Yes for practical purposes with IT definitions. Thermochemical constants differ slightly; use the full converter if your lab explicitly requires cal (th).