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Kilocalories to Calories Converter

Convert Kilocalories (kcal) to Calories (cal) instantly, or use the conversion table below to look up common values.

1 kcal = 1,000 cal

Kilocalories to Calories conversion table

Kilocalories (kcal)Calories (cal)
11,000
22,000
33,000
44,000
55,000
1010,000
2525,000
5050,000
100100,000

How to convert Kilocalories to Calories

1 kcal equals 1,000 cal. Use the converter above for any value, or read the table for common conversions.

cal = kcal × 1000 · kcal = cal × 0.001

Multiply a kilocalories figure by 1,000 to get calories, or divide it by 0.001 to go the other way.

Worked examples

  • 1 kcal= 1,000 cal
  • 5 kcal= 5,000 cal
  • 10 kcal= 10,000 cal
  • 100 kcal= 100,000 cal
  • 500 kcal= 500,000 cal

What these units are

Kilocalories (kcal). A kilocalorie is 1,000 calories, or 4,184 joules. It is the 'calorie' on food labels, so a 2,000-calorie diet means 2,000 kilocalories.

Calories (cal). A calorie here is the small calorie of 4.184 joules — the energy needed to raise one gram of water by one degree Celsius. Food labels use the kilocalorie, which is 1,000 of these.

All factors are exact definitions, so only the display is rounded.

Converting Kilocalories to Calories in practice

Working in kilocalories

Exactly 1,000 thermochemical calories, or 4,184 joules, make one kilocalorie. A food label that prints calorie, often with a capital letter, means this unit rather than the small calorie of physics.

Food energy on packaging, diet plans, restaurant menus and sports nutrition is stated in kilocalories. Physiology and nutrition research also reports energy expenditure in the same unit.

Kilocalories convert to kilojoules by the exact factor 4.184, and to joules by 4,184, with no rounding. Since a kilowatt-hour is 3.6 megajoules, one kilocalorie is a little over 0.00116 kilowatt-hours.

The standard mistake is to treat the label's calorie as the small calorie and conclude that food holds far less energy than it does. The label unit is one thousand small calories.

The kilocalorie is the label unit, the calorie is its one-thousandth in physics, and the kilojoule is the metric equivalent at 4.184 kilojoules each. A diet figure and a physics figure therefore need different units before they can be compared.

Reading the result in calories

One thermochemical calorie is exactly 4.184 joules, a definition fixed by convention rather than by a water experiment. The food calorie on a nutrition label is a kilocalorie of 4,184 joules.

The small calorie appears in chemistry, physics and heat-capacity problems, where a substance's specific heat is expressed per gram per degree. Nutrition labels use the much larger food calorie instead.

Calories convert to joules by the exact factor 4.184, and kilocalories by 4,184, so no precision is lost in either direction. One kilocalorie is about 4.184 kilojoules, the same amount under another name.

Reading a nutrition label's calorie value as small calories understates the energy by a factor of one thousand. The figure printed there is always the kilocalorie, however it is capitalised or labelled.

The calorie shares its dimension with the kilocalorie, the joule and the kilojoule, and mixing them is the risk. A food label's figure is a kilocalorie, while mechanics and heat problems work in joules and kilojoules.

Checking a kilocalories to calories conversion

Energy units are defined against the joule, so every conversion in this dimension is a single exact multiplication by a published number rather than a chain of steps that could accumulate error.

The pair that needs care is the kilowatt-hour, because it looks like a power unit and is not. It is a watt sustained for an hour, which is why an electricity meter counts in kilowatt-hours while a generator is rated in kilowatts: one is an amount, the other is a rate, and only a duration links them.

To check an energy conversion, express both sides in joules or both in kilowatt-hours before comparing. The commonest mistake is treating a food calorie as a calorie when the label means a kilocalorie, which understates the figure a thousandfold.

Tanzania reference points

Real quantities, converted into the units on this page.

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