Kilocalories (kcal) to Joules (j) Converter

What is Energy?

Energy is the capacity to do work. It exists in many forms, including kinetic energy, potential energy, thermal energy, and chemical energy. The SI unit of energy is the Joule (J), but there are many other commonly used energy units.

Common Energy Units and Their Uses

• Joule (J): The SI unit of energy, commonly used in physics.
• Kilojoule (kJ): 1,000 Joules; often used in nutrition and chemistry.
• Calorie (cal): The energy needed to raise 1 gram of water by 1°C.
• Kilocalorie (kcal): 1,000 calories; commonly known as a 'food calorie'.
• Watt-hour (Wh): Used to measure electrical energy consumption.
• Kilowatt-hour (kWh): 1,000 watt-hours; seen on electricity bills.
• British Thermal Unit (BTU): Common in heating and air conditioning systems.
• Electron Volt (eV): Used in atomic and particle physics.

How to Convert Energy Units?

Energy unit conversion is based on specific formulas. For example, 1 kcal = 4.184 kJ and 1 kWh = 3.6 MJ. Our energy converter tool allows instant conversions between various units.

How Many Joules in a Calorie?

1 calorie (small calorie) is equal to 4.184 Joules. However, food energy is measured in kilocalories (kcal), so 1 kcal = 4,184 J.

What is a Kilowatt-Hour (kWh)?

A kilowatt-hour (kWh) is a unit of energy equal to 1,000 watt-hours. It is widely used to measure electricity consumption. For reference, a 100W light bulb running for 10 hours consumes 1 kWh.

What is the Difference Between kcal and Cal?

In scientific terms, 1 calorie (cal) is the energy needed to heat 1 gram of water by 1°C. However, in food labeling, 1 Calorie (Cal) (capital C) refers to 1 kilocalorie (kcal), which equals 1,000 small calories.

How Much Energy Does the Sun Provide?

The Sun emits about 3.8 × 10²⁶ Joules per second, but only a fraction reaches Earth. This energy drives weather, ocean currents, and plant photosynthesis.

How Many Joules in 1 kWh?

1 kilowatt-hour (kWh) is equal to 3,600,000 Joules (3.6 MJ). This is the energy used by a 1,000-watt appliance running for one hour.

What is a British Thermal Unit (BTU)?

A BTU (British Thermal Unit) is the amount of energy needed to heat one pound of water by 1°F. It is commonly used in air conditioning and heating industries.

How Many Calories Should I Consume Daily?

Daily calorie needs vary based on age, gender, and activity level. The general guideline is:

• Sedentary Women: 1,600–2,000 kcal/day
• Active Women: 2,000–2,400 kcal/day
• Sedentary Men: 2,000–2,400 kcal/day
• Active Men: 2,400–3,000 kcal/day

How Much Energy is in a Gallon of Gasoline?

A gallon of gasoline contains about 120,000 BTU, which is approximately 33.6 kWh or 121 MJ. This high energy density makes gasoline an effective fuel.

How Efficient is Human Energy Use?

The human body converts food into usable energy with about 20–25% efficiency. The rest is lost as heat. This is why humans generate body heat during exercise.

What is the Energy of a Lightning Bolt?

A typical lightning bolt carries about 1 billion Joules of energy, enough to power a 100W bulb for over 3 months!