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kJ ↔ kcal Converter
Many food labels list energy in kilojoules (kJ), kilocalories (kcal) or both. Type a value in either field and the other fills in: 1 kcal = 4.184 kJ. It runs entirely in your browser; nothing you type is sent or stored.
Worked example: 250 kcal × 4.184 = 1046 kJ. Going back, 1000 kJ ÷ 4.184 = 239.01 kcal.
Frequently asked questions
How many kJ are in one kcal?
1 kcal = 4.184 kJ. Multiply kcal by 4.184 to get kJ, or divide kJ by 4.184 to get kcal.
Why can a label differ slightly from this result?
Label values are rounded, so the printed kcal and kJ can differ a little from an exact conversion. This converter uses 4.184 and rounds to two decimal places.
Can I skip typing the label?
Yes. Nyamly, an iPhone app that is free to download, reads a product's nutrition facts straight from its barcode, so there is no manual entry and no photographing a label.
Skip typing the label: scan the barcode
Nyamly is an iPhone calorie tracker and barcode scanner, free to download. It reads a product's nutrition facts straight from its barcode — no manual entry, no photographing a label.