Joules to Kilocalories Converter
Common Conversions
| J | kcal |
|---|---|
| 4.184 | 0.001 |
| 41.84 | 0.01 |
| 418.4 | 0.1 |
| 4184 | 1 |
| 20920 | 5 |
| 41840 | 10 |
| 104600 | 25 |
| 209200 | 50 |
| 418400 | 100 |
| 1046000 | 250 |
| 2092000 | 500 |
| 4184000 | 1000 |
Why this conversion matters in chemistry
Bomb calorimetry returns total combustion heat in joules; biochemistry textbooks tabulate the same enthalpies in kcal/mol. Glucose combustion is −2803 kJ/mol on a modern data sheet, equivalently −670 kcal/mol in a metabolism textbook. Palmitic acid runs about −10,035 kJ/mol, or −2398 kcal/mol. Dividing by 4184 is the conversion that lines up an instrument-raw joule reading against the kcal/mol values in a biochemistry data table. The factor is exact through the thermochemical calorie definition (1 cal = 4.184 J, by IUPAC convention).
Formula
Worked Examples
The defining identity of the thermochemical kilocalorie.
Roughly the energy of a typical small snack — useful as a reality check for nutritional-biochemistry reasoning.
The standard enthalpy of formation of gaseous water (magnitude only; the actual value is negative). Liquid water sits higher in magnitude at 285.8 kJ/mol or 68.3 kcal/mol.
One thermochemical calorie — the small-cal unit that sits below the kcal scale food labels actually use.