Energy Converter
Instantly convert between Joules, Calories, Kilocalories, Kilowatt-hours, BTU, and Electron Volts.
Result
0.239006 Calorie (cal)
1 Joule (J) = 0.239006 Calorie (cal)
Common Energy Conversions
| From | To |
|---|---|
| 1 kcal | 4,184 J |
| 1 kWh | 3,600,000 J |
| 1 BTU | 1,055.06 J |
| 1 cal | 4.184 J |
| 1 kWh | 3,412.14 BTU |
| 1 kcal | 3.968 BTU |
What Is Energy in Physics?
Energy is one of the most fundamental concepts in physics. It is defined as the capacity to do work or produce change. The SI unit of energy is the joule (J), named after James Prescott Joule, a 19th-century English physicist who studied the relationship between heat and mechanical work. One joule is equal to the energy transferred when a force of one Newton moves an object one meter. Energy exists in many forms -- kinetic, potential, thermal, chemical, electrical, nuclear, and radiant -- and can be converted from one form to another but never created or destroyed, according to the law of conservation of energy. This principle underpins virtually all of modern science and engineering, from the combustion engine to nuclear power plants.
Calories in Nutrition and Food Science
In nutrition, the term "Calorie" (with a capital C) actually refers to a kilocalorie (kcal), which equals 1,000 small calories. One kilocalorie is the energy required to raise the temperature of one kilogram of water by one degree Celsius. When a food label states that a serving contains 200 Calories, it means 200 kcal, or 836,800 joules. This distinction can be confusing, but it is important for anyone tracking dietary intake or studying food science. The human body converts the chemical energy stored in carbohydrates, fats, and proteins into usable energy for cellular processes, movement, and maintaining body temperature. An average adult requires about 2,000 to 2,500 kcal per day, though this varies widely based on age, activity level, and metabolic rate.
Electricity Billing and Kilowatt-Hours
The kilowatt-hour (kWh) is the standard unit used by electric utilities worldwide to measure and bill energy consumption. One kWh equals the energy consumed by a 1,000-watt appliance running for one hour, which is equivalent to 3.6 million joules. Understanding your kWh usage is the key to managing electricity costs. For example, a 100-watt light bulb running for 10 hours consumes 1 kWh. As renewable energy sources like solar and wind become more prevalent, homeowners with solar panels often monitor their generation in kWh to understand how much energy they produce versus consume. Net metering programs allow surplus kWh generated by home solar systems to be credited back to the grid, effectively spinning the meter backward and reducing monthly bills.
BTU and Heat Measurement in HVAC
The British Thermal Unit (BTU) is widely used in the heating, ventilation, and air conditioning (HVAC) industry, particularly in North America. One BTU is the amount of heat needed to raise the temperature of one pound of water by one degree Fahrenheit, approximately 1,055.06 joules. Air conditioners, furnaces, and water heaters are commonly rated in BTU per hour (BTU/h) to indicate their heating or cooling capacity. A typical window air conditioner might be rated at 8,000 to 12,000 BTU/h, while a residential furnace may produce 40,000 to 100,000 BTU/h. In the natural gas industry, energy content is often expressed in therms (1 therm = 100,000 BTU). Engineers and technicians regularly convert between BTU, joules, and kWh when designing systems, comparing fuel sources, or evaluating energy efficiency. Our energy converter makes these conversions fast and reliable, supporting professionals and students alike in their energy calculations.
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