Kcal to Calories Converter
Two different units are called a calorie, and which one you mean decides the answer. The small calorie, the gram calorie of physics and chemistry, is 4.184 joules, and that is the unit this page converts into: cal = kcal × 1,000, so 1 kcal is 1,000 cal, 7 kcal is 7,000 cal, 250 kcal is 250,000 cal and 2,000 kcal is 2,000,000 cal. The large Calorie with a capital C, the one a nutrition label prints, is the kilocalorie itself, so a label reading 250 Calories describes the same quantity as 250 kcal and the conversion between those two is 1 for 1. This page opens the converter with Kilocalorie (kcal) in the From box and Calorie (cal) in the To box, ahead of whatever pair you converted last, and the list under the answer carries the same energy in joules, kilojoules, watt hours, kilowatt hours and British thermal units, where 1 kcal is 4,184 J, 4.184 kJ, 1.16222222222 Wh, 0.00116222222222 kWh and 3.96566683139 BTU. The thousand between the two calories is an SI prefix rather than a measurement, so the kcal to cal step is exact whichever definition of the calorie your source used.
1 kcal in every energy unit
Common questions
- How many calories are in 1 kcal?
- 1,000 of the small calories this page converts into, and 1 of the large Calories a food label prints. In the small unit it scales straight up: 0.25 kcal is 250 cal, 7 kcal is 7,000 cal, 100 kcal is 100,000 cal, 1,500 kcal is 1,500,000 cal and 3,500 kcal is 3,500,000 cal. Going the other way, 500 cal is 0.5 kcal, 250,000 cal is 250 kcal and 2,000,000 cal is 2,000 kcal.
- Which calorie does this page convert to, the small one or the food Calorie?
- The small one. The energy list holds Calorie (cal) at 4.184 joules, the gram calorie, and Kilocalorie (kcal) at 4,184 joules, which is the unit a nutrition label writes as Calorie with a capital C. So the headline answers the science question, 1 kcal into 1,000 cal. If your figure came off a packet and you want the label's own unit, the answer is the number you already have, and the useful rows are the ones underneath: 250 kcal is 1,046 kJ and 1,046,000 J.
- What is the formula for kcal to calories?
- cal = kcal × 1,000, and kcal = cal / 1,000 in the other direction. Both units sit on the same joule scale in this table, 4,184 J for the kilocalorie and 4.184 J for the calorie, so the factor of a thousand between them is the prefix and nothing more. The swap button between the two boxes reverses the pair, which turns this into a calories to kcal page without a reload: 500 cal reads 0.5 kcal and 2,000,000 cal reads 2,000 kcal.
- Why do kcal and Calories look interchangeable on food packaging?
- Because on that panel they are the same unit under two names: the large Calorie is the kilocalorie, and the capital letter is the only thing distinguishing it from the small calorie. A panel that says 250 Calories and 250 kcal is printing one quantity twice. Where the same panel also carries kilojoules, the tie is fixed: 250 kcal is 1,046 kJ, 500 kcal is 2,092 kJ and 2,000 kcal is 8,368 kJ. In the small calorie those three figures are 250,000 cal, 500,000 cal and 2,000,000 cal.
- Is a calorie 4.184 joules or 4.1868 joules?
- Both values are in use and this table uses the first. The thermochemical calorie is exactly 4.184 J by definition, and Calorie (cal) and Kilocalorie (kcal) are built on it here, so 1 cal reads 4.184 J and 1 kcal reads 4,184 J. The International Table calorie is 4.1868 J, which would put the same kilocalorie at 4,186.8 J, about 0.07 percent higher, and the 15 degree calorie is a third value near 4.1855 J. None of that moves the answer on this page, because kcal to cal is a factor of 1,000 under every one of those definitions.
- How many joules and watt hours is 1 kcal?
- 4,184 J, 4.184 kJ, 1.16222222222 Wh, 0.00116222222222 kWh and 3.96566683139 BTU, all of them listed under the answer as soon as you type. For a 2,000 kcal figure the same rows read 8,368,000 J, 8,368 kJ, 2,324.44444444 Wh, 2.32444444444 kWh and 7,931.33366278 BTU. Each row has its own Copy button, and Copy result in the strip above copies the headline calorie figure without the thousands separators it is displayed with.
- Does the list under the answer repeat kilocalories?
- No. The list shows every other unit in the energy category and skips the one in the From box, so here it reads joule, kilojoule, calorie, watt hour, kilowatt hour and British thermal unit. The readout strip also carries an Uncommon units switch labelled Show 1 more, which adds the electronvolt: 1 kcal is 2.611447e22 eV. Results print to twelve significant digits, and a magnitude at or above 1e15, or below 0.000001, is shown in exponential notation, which is why that one arrives with an exponent.
- Why does the page open on kcal and cal when I last converted something else?
- Because a page that names a pair should show that pair. This one sets Kilocalorie and Calorie on arrival, ahead of whatever the converter last remembered, and it leaves the main unit converter's own pair alone: go back there and it is still on the units you left it on. The number you last typed does travel with you, along with the uncommon units switch, since that is usually the figure you are still working on.
Conversion factors are the exact legal definitions where one exists. An inch is exactly 2.54 cm and a pound exactly 0.45359237 kg, so those conversions are exact rather than approximate. Temperature uses offsets rather than factors, and that is shown in the working.