Kilocalories to Kilojoules Converter

How many kilojoules in 1 kcal?

1 kcal = 4.184 kJ. The other way round: 1 kJ = 0.2390057361 kcal. The kilocalorie (the “Calorie” on food labels) is the energy needed to heat 1 kg of water by 1 °C; the thermochemical definition is exactly 4.184 kJ. The kilojoule is the SI energy unit; EU and Australian food labels must show energy in kJ alongside kcal.

Kilocalories to kilojoules conversion table

1 kcal = 4.184 kJ · 2 kcal = 8.368 kJ · 3 kcal = 12.552 kJ · 4 kcal = 16.736 kJ · 5 kcal = 20.92 kJ · 6 kcal = 25.104 kJ · 7 kcal = 29.288 kJ · 8 kcal = 33.472 kJ · 9 kcal = 37.656 kJ · 10 kcal = 41.84 kJ · 12 kcal = 50.208 kJ · 15 kcal = 62.76 kJ · 20 kcal = 83.68 kJ · 25 kcal = 104.6 kJ · 30 kcal = 125.52 kJ · 40 kcal = 167.36 kJ · 50 kcal = 209.2 kJ · 75 kcal = 313.8 kJ · 100 kcal = 418.4 kJ · 1,000 kcal = 4,184 kJ

How to convert kilocalories to kilojoules

Multiply the value by 4.184. Example: 37 kcal = 154.808 kJ.

Unit Converter

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How to use

1. 1Pick a category — length, weight, temperature, volume, area, speed, data, time, pressure or energy.
2. 2Choose the “from” and “to” units, or press swap to reverse them.
3. 3Type a value in either field — the other side updates as you type.
4. 4Adjust the decimal precision and check the conversion table for common values.

Exact conversion factors

Many imperial units are defined exactly in metric terms: 1 inch = 2.54 cm, 1 foot = 0.3048 m, 1 mile = 1.609344 km, 1 pound = 0.45359237 kg and 1 US gallon = 3.785411784 litres. The converter uses these definitions, so results are as precise as the decimals you choose to show. The formula is displayed in words — for example “multiply by 2.54” — so you can repeat the calculation by hand.

Temperature is different

Celsius, Fahrenheit and Kelvin do not share a zero point, so temperature cannot be converted with a single factor. °F = °C × 9/5 + 32 and °C = (°F − 32) × 5/9; Kelvin is Celsius + 273.15. That is why 0 °C is 32 °F, while a 10-degree change in Celsius is an 18-degree change in Fahrenheit.

US vs UK units and data sizes

A US gallon (3.785 L) is smaller than an imperial UK gallon (4.546 L), and US fluid ounces differ slightly from UK ones — check which system your recipe or spec uses. For data sizes, storage makers use decimal units (1 GB = 1,000 MB), while operating systems often count in binary units (1 GiB = 1,024 MiB), which is why a new drive shows less capacity than the label.

Frequently asked questions

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