Cal to kcal converter, calories to kilocalories.

To convert cal to kcal, divide the calories by 1,000. So 1,000 cal is 1 kcal, 250,000 cal is 250 kcal and 2,000,000 cal is 2,000 kcal. The reverse is a multiplication by 1,000. The sum is exact, because the prefix "kilo" means exactly 1,000, and it holds for every kind of calorie.

How to use the converter

1. Type the number in the Calories (cal) box. The page opens on 250,000 cal, which is a 250 Calorie snack written in small calories.
2. Read the big result in Kilocalories (kcal). The cards below give the same energy in joules and kilojoules.
3. Press the swap button (or the S key) to go from kcal to cal. Type 500 in the kilocalorie box and you get 500,000 cal.
4. Use Copy result or Copy link, click a row in Common values, or Print chart for a small table.

Cal, kcal and the Calorie with a capital C

There are two sizes of unit in everyday talk, and they share one word. The small calorie (cal, with a small c) is a few joules of energy. The kilocalorie (kcal) is 1,000 of them. People also write the kilocalorie as "Calorie" with a capital C, and that is the unit on food packaging. A snack that says 250 Calories holds 250 kcal, which is 250,000 small calories. If you type 250 into the cal box you are asking about a very small amount, 0.25 kcal, which is about 1,046 J.

The rule that keeps you safe: if a number comes from a nutrition label, a menu or a fitness app, it is already in kilocalories, whatever the word on the page is. You only need cal to kcal when a source uses the small calorie, as some chemistry and physics texts do.

The four names side by side

The first three are tied together by exact factors of 1,000, and the third is simply the second written with a capital letter. The International Table calorie is a different definition of the same name. It matters only when you convert to joules.

A label read in both ways

Say a pack lists 110 Calories per serving and holds 2 servings. The pack has 220 Calories, or 220 kcal, which is 220,000 cal in small calories and 920.5 kJ. A label figure like this is already the kilocalorie number, so the cal box is only for texts that use the small calorie.

Exact joule values

NIST Special Publication 811, Appendix B.8 (checked 26 Oct 2026) marks the thermochemical calorie as exactly 4.184 J and the thermochemical kilocalorie as exactly 4,184 J. It lists the same 4,184 J for the "nutrition" Calorie. A second version, the International Table calorie, is exactly 4.1868 J, which is 0.07 percent larger. This page uses the thermochemical values, and that choice does not change cal to kcal because both units move together. It only matters when you go on to joules. 250 kcal is 1,046 kJ here, and it would be about 1,046.7 kJ with the International Table calorie.

The US Food and Drug Administration page on calories (checked 26 Oct 2026) explains that calories on the label are the energy you get from carbohydrate, fat, protein and alcohol in a serving, and uses 2,000 calories a day as a general guide for nutrition advice. In small calories that guide is 2,000,000 cal, or 8,368 kJ.

Worked examples

• 1,500 cal. 1,500 ÷ 1,000 = 1.5 kcal. That is 6,276 joules.
• A 250 Calorie snack in small calories. 250 kcal × 1,000 = 250,000 cal.
• A 2,000 Calorie day. 2,000,000 cal, or 8,368 kJ.
• 100 cal of heat in a lab. 0.1 kcal, or 418.4 J.
• One kilowatt-hour. 3,600,000 J ÷ 4,184 = 860.42 kcal.

Mistakes people make

The common one is multiplying a label Calorie by 1,000 when the aim is joules. Calories to joules uses 4.184, not 1,000. A 250 Calorie snack is 250 × 4.184 = 1,046 kJ. The second is treating "cal" on a fitness app as a small calorie. Apps nearly always mean kilocalories.

Heat and water, a way to picture it

A small calorie is roughly the heat needed to warm 1 gram of water by 1 degree Celsius. A kilocalorie warms 1 kilogram of water by about 1 degree. Those are rounded pictures, and the exact joule values above are the ones that count.

Table of everyday sizes

For energy in kilojoules see KJ to calories. For the large units see MJ to J. To estimate how many Calories you burn in a day, use the TDEE calculator or the BMR calculator.