Convert Kilocalories to Exajoules
Convert Kilocalories (kcal) to Exajoules (EJ) instantly and accurately.
Conversion Formula
EJ = kcal × 4.184000000e-15
About Kilocalories
A kilocalorie (kcal) - the food Calorie (capital C) on US and Canadian nutrition labels - is exactly 4,184 J. WHO recommends ~2,000-2,500 kcal/day for adults. Energy density of nutrients: fat 9 kcal/g, carbohydrate 4 kcal/g, protein 4 kcal/g, ethanol 7 kcal/g. Running at 10 km/h burns ~600-800 kcal/h. Standard free energy of ATP hydrolysis is approximately −7.3 kcal/mol (−30.5 kJ/mol). Pre-SI thermodynamic tables in the US and Japan use kcal/mol for reaction enthalpies. 1 kcal = 4,184 J = 4.184 kJ = 3.968 BTU = 1.163 Wh.
About Exajoules
An exajoule (EJ) is 10¹⁸ J - the scale of global energy consumption. World primary energy supply in 2022 was ~580-610 EJ: coal ~160 EJ; oil ~190 EJ; gas ~145 EJ; nuclear ~26 EJ; wind ~8 EJ; solar PV ~8 EJ. Global electricity generation of ~29,000 TWh = 104 EJ. Solar energy incident on Earth's atmosphere is ~5.5 × 10⁶ EJ/year - approximately 9,000× total human demand. Annual fossil fuel combustion releases ~490 EJ/year, producing ~36.8 Gt CO₂. 1 EJ = 10¹⁸ J = 277.78 TWh = 238.85 Mtoe.
Quick Reference Table
| Kilocalories (kcal) | Exajoules (EJ) |
|---|---|
| 1 kcal | 4.184 × 10-15 EJ |
| 2 kcal | 8.368 × 10-15 EJ |
| 5 kcal | 2.092 × 10-14 EJ |
| 10 kcal | 4.184 × 10-14 EJ |
| 25 kcal | 1.046 × 10-13 EJ |
| 50 kcal | 2.092 × 10-13 EJ |
| 100 kcal | 4.184 × 10-13 EJ |