Kilocalories to Calories Converter

Convert kilocalories to calories instantly with our free energy conversion calculator. Enter any value for accurate results.

How to Convert Kilocalories to Calories

To convert an energy measurement from kilocalories to calories, multiply the energy value by the conversion factor. Since one kilocalorie is equal to 1,000 calories, you can use this formula:

calories = kilocalories × 1,000

The energy in calories is equal to the kilocalories multiplied by 1,000.

Example: Convert 5 kilocalories to calories.

Using the formula: calories = kilocalories × 1,000

calories = 5 kcal × 1,000 = 5,000 cal

Therefore, 5 kilocalories equals 5,000 calories.

How Many Calories Are in a Kilocalorie?

There are 1,000 calories in one kilocalorie.

1 kcal = 1,000 cal

What Is a Kilocalorie?

The kilocalorie (symbol: kcal) is a unit of energy equal to 1,000 thermochemical calories or 4,184 joules. It is also known as the “food calorie,” the “large calorie,” or simply “Calorie” (with an uppercase “C”). The kilocalorie is the standard unit used on food nutrition labels in the United States and many other countries. When a food label states that a serving contains “200 Calories,” it means 200 kilocalories (200,000 small calories or 837 kJ). A typical adult requires about 2,000–2,500 kcal per day, depending on age, sex, weight, and activity level. Common food energy values include: a medium apple (~95 kcal), a slice of bread (~70–80 kcal), a cup of cooked rice (~200 kcal), and a typical fast-food burger (~500–700 kcal). In exercise science, the kilocalorie is used to measure the energy expenditure of physical activities. Walking for 30 minutes burns about 100–200 kcal, running for 30 minutes burns about 200–400 kcal, and swimming for 30 minutes burns about 200–350 kcal, depending on intensity and body weight.

One kilocalorie is equal to:

4,184 joules (J)
4.184 kilojoules (kJ)
1,000 calories (cal)
1.162 watt-hours (Wh)
3.966 BTU
2.6117 × 10²² electronvolts (eV)

What Is a Calorie?

The calorie (symbol: cal), specifically the thermochemical calorie, is a unit of energy defined as exactly 4.184 joules. It was originally defined as the amount of heat needed to raise the temperature of one gram of water by one degree Celsius (from 14.5 °C to 15.5 °C). The calorie (lowercase “c”) is also called the “small calorie” or “gram calorie” to distinguish it from the kilocalorie (often written as “Calorie” with uppercase “C”), which equals 1,000 small calories and is the unit commonly used on food nutrition labels in the United States. In chemistry, the calorie is used to express specific heat capacities, enthalpies of reaction, and activation energies. By definition, the specific heat capacity of water is 1 cal/(g·°C), making the calorie a natural unit for calorimetry experiments. Although the joule has officially replaced the calorie in the SI system, the calorie remains widely used in nutrition, chemistry, and some branches of engineering due to its historical significance and practical convenience in water-based heat calculations.

One calorie is equal to:

4.184 joules (J)
0.004184 kilojoules (kJ)
0.001 kilocalories (kcal)
0.001162 watt-hours (Wh)
0.003966 BTU
2.6117 × 10¹⁹ electronvolts (eV)

Understanding Energy Units

Energy is a fundamental physical quantity that represents the capacity to do work or produce heat. It is conserved in all physical processes (the first law of thermodynamics) and can be converted from one form to another — mechanical, thermal, electrical, chemical, nuclear, and radiant energy are all interconvertible.

The wide variety of energy units reflects the historical development of different branches of science and engineering, each of which developed its own preferred units before the adoption of the International System of Units (SI).

Major Unit Families

SI / Metric units: The joule (J) is the SI unit of energy, with standard metric prefixes (kJ, MJ, GJ). The watt-second (Ws) is identical to the joule. Watt-hours (Wh), kilowatt-hours (kWh), and megawatt-hours (MWh) combine power (watts) with time.
Calorie-based units: The calorie (cal), kilocalorie (kcal), and megacalorie (Mcal) originated in thermochemistry. The kilocalorie is widely used in nutrition as the “food Calorie.”
British / Imperial units: The British thermal unit (BTU) and its multiples (MMBTU, therm, quad) are used primarily in the US for HVAC, natural gas, and national energy statistics.
Atomic-scale units: The electronvolt (eV) and its multiples (keV, MeV) are used in atomic, nuclear, and particle physics for the extremely small energies of individual particles.

Energy in Everyday Life

Nutrition: Food energy is measured in kilocalories (kcal) or kilojoules (kJ). A typical adult needs about 2,000–2,500 kcal (8,400–10,500 kJ) per day.
Electricity: Household electricity consumption is measured in kilowatt-hours (kWh). An average US home uses about 900–1,000 kWh per month.
Heating: Natural gas consumption is measured in therms or MMBTU. A US home might use 500–1,000 therms per year for heating.
Transportation: Gasoline contains about 120,000 BTU or 34 MJ per litre. One gallon of gasoline contains about 33.7 kWh of energy.

Converting Between Energy Units

All energy units measure the same physical quantity, so converting between them is simply a matter of multiplying by the appropriate conversion factor. The factor is the ratio of how many joules one unit of the source contains divided by how many joules one unit of the target contains.

For very large or very small conversion factors, results are often expressed in scientific notation (e.g., 6.2415 × 10¹⁸ eV per joule). This is particularly common when converting between atomic-scale units (electronvolts) and everyday units (joules, BTU, calories).

Tips for Energy Conversions

The joule and watt-second are exactly the same unit (1 J = 1 Ws). The different names are used in different contexts.
For SI metric conversions (J, kJ, MJ, GJ), each prefix step is a factor of 1,000. The same applies to cal/kcal/Mcal, Wh/kWh/MWh, and eV/keV/MeV.
The kilocalorie (kcal) used in nutrition is often written as “Calorie” with a capital C. When a food label says 200 Calories, it means 200 kcal = 200,000 cal.
One kilowatt-hour equals exactly 3,600,000 joules (1 kW × 3,600 seconds). This is useful for converting between electrical and metric energy units.
One BTU ≈ 1,055 joules ≈ 252 calories. These rough equivalences are useful for quick mental conversions.
One therm = 100,000 BTU exactly. One MMBTU = 1,000,000 BTU exactly. One quad = 10¹⁵ BTU exactly.
The electronvolt is an extremely small unit compared to everyday energy: 1 eV ≈ 1.6 × 10⁻¹⁹ J. It is used only for atomic-scale energies.
To calculate electricity cost, multiply kWh × price per kWh. To calculate gas heating cost, multiply therms × price per therm.

Kilocalories to Calories Conversion Table

The following table shows conversions from kilocalories to calories.

Kilocalories	Calories (cal)
1 kcal	1,000
2 kcal	2,000
3 kcal	3,000
4 kcal	4,000
5 kcal	5,000
6 kcal	6,000
7 kcal	7,000
8 kcal	8,000
9 kcal	9,000
10 kcal	10,000
11 kcal	11,000
12 kcal	12,000
13 kcal	13,000
14 kcal	14,000
15 kcal	15,000
16 kcal	16,000
17 kcal	17,000
18 kcal	18,000
19 kcal	19,000
20 kcal	20,000
21 kcal	21,000
22 kcal	22,000
23 kcal	23,000
24 kcal	24,000
25 kcal	25,000
26 kcal	26,000
27 kcal	27,000
28 kcal	28,000
29 kcal	29,000
30 kcal	30,000
31 kcal	31,000
32 kcal	32,000
33 kcal	33,000
34 kcal	34,000
35 kcal	35,000
36 kcal	36,000
37 kcal	37,000
38 kcal	38,000
39 kcal	39,000
40 kcal	40,000