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Energy
Calories to Kilocalories
Convert calories (cal) to kilocalories (kcal). Type a value below to see the result update instantly. Reference table and formula included.
Calculator
1 cal = 0.001 kcal
Calories to Kilocalories Conversion Table
Common values, ready to copy:
| calories | kilocalories |
|---|---|
| 1 cal | 0.001 kcal |
| 2 cal | 0.002 kcal |
| 5 cal | 0.005 kcal |
| 10 cal | 0.01 kcal |
| 25 cal | 0.025 kcal |
| 50 cal | 0.05 kcal |
| 100 cal | 0.1 kcal |
| 1,000 cal | 1 kcal |
Formula
kilocalories = calories × 0.001
Energy uses the SI joule. Food calories (kcal) are 1,000 small calories: 1 kcal = 4,184 J. 1 kWh = 3.6 MJ = 3,600,000 J. 1 BTU = 1,055.06 J.
About Calories and Kilocalories
Calories (cal): Originally defined as the energy to raise one gram of water by one degree Celsius; exactly 4.184 J in the modern definition (the thermochemical calorie). Common uses: Scientific work in chemistry, where the small calorie is the natural unit for heat-of-reaction measurements.
Kilocalories (kcal): A thousand small calories, or about 4,184 J; this is what 'calories' means on US food labels. Common uses: Food energy labeling in the US (a 'Calorie' on a US food label is a kilocalorie), nutrition tracking, and exercise energy expenditure.
How the conversion works
Energy uses the SI joule. Food calories (kcal) are 1,000 small calories: 1 kcal = 4,184 J. 1 kWh = 3.6 MJ = 3,600,000 J. 1 BTU = 1,055.06 J.
The exact relationship is kilocalories = calories × 0.001, which the calculator at the top of this page applies in both directions. Type into either field and the other updates immediately.
When this conversion matters
Converting between calories and kilocalories comes up wherever energy measurements move between systems — from one country's conventions to another's, from a scientific reference to a practical specification, or from one industry's working unit to another's. The calculator and reference table above cover the everyday range; for unusual values you can type any number into either field.