Kilocalories to Kilojoules Converter

Food labels in the United States show Calories, which are kilocalories, while labels in Australia, New Zealand and parts of Europe show kilojoules, often alongside kcal. One kilocalorie is exactly 4.184 kilojoules under the thermochemical definition, so 2,000 kcal is 8,368 kJ.

1. 1

   Enter a value

   Type a number into the From box. It starts at 1 so you can see the basic ratio straight away. Thousands separators such as 1,250.5 are accepted.

2. 2

   Choose your units

   This page opens with its own units selected. Use either dropdown to pick any other unit in the category, or tap a unit in the all-units list to make it the target.

3. 3

   Read the result

   The answer updates as you type and the matching formula is shown underneath. There is no Convert button to press.

4. 4

   Swap, copy or clear

   Swap reverses the direction, Copy Result copies a line such as 1 km = 0.621371 mi, and Clear empties the input so you can start again.

Input

• Supported
  Whole numbers25
• Supported
  Decimal numbers2.75

  Use a dot as the decimal separator.

• Supported
  Negative numbers-40

  Calculated for every unit. Quantities such as length or weight are normally positive, while temperatures can be negative.

• Supported
  Thousands separators1,250.5

  Commas must group digits in threes. 1,234 is read as one thousand two hundred thirty-four.

• Supported
  Scientific notation1.5e6

  Useful for very large or very small values (1.5e6 = 1,500,000).

• Not supported
  Comma as decimal mark2,5

  Type 2.5 instead.

• Not supported
  Fractions1/2

  Type 0.5 instead.

• Not supported
  Numbers with unit text5 km

  Enter only the number and choose the unit from the dropdown.

Output

Results use US English formatting (1,234.56) and show up to 6 decimal places with trailing zeros removed. Very small results appear in scientific notation, such as 9.0949e-13, instead of rounding to zero.

Units available in this converter

• Joule (J)
• Kilojoule (kJ)
• Calorie (cal)
• Kilocalorie (kcal)
• Watt Hour (Wh)
• Kilowatt Hour (kWh)

Common values for the units currently selected above, in both directions.

Tips

• A capital-C Calorie on a label equals one kilocalorie, while a lowercase calorie (cal) is 1,000 times smaller.
• Quick estimate: multiply kcal by 4.2 to get kJ.

• The calorie is the thermochemical calorie (4.184 J). Calories on food labels are kilocalories.
• Energy is not power: a kilowatt-hour is different from a kilowatt. BTU and electronvolt are not supported.
• Results show up to 6 decimal places. Values are not rounded during calculation, and a non-zero result that would display as 0 is shown in scientific notation.