Convert Petajoules to Kilocalories

Convert Petajoules (PJ) to Kilocalories (kcal) instantly and accurately.

Conversion Formula

kcal = PJ × 239005736100

About Petajoules

A petajoule (PJ) is 10¹⁵ J - the national energy policy scale. IEA reports primary energy in PJ/year: Sweden ~600 PJ; Germany ~12,500 PJ; the United States ~93,000 PJ. World total primary energy supply is ~605,000 PJ = 605 EJ. The 1883 Krakatoa eruption released ~200 PJ ≈ 48 megatons TNT. A 1-megaton nuclear weapon releases 4.184 PJ. Global annual steel production embeds ~38,000-47,000 PJ of energy. 1 PJ = 10¹⁵ J = 277.78 GWh = 238.85 ktoe = 23.88 ktoe.

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.

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