1 Kcal to Kj – Answer and Calculator Tool

1 kilocalorie (kcal) is equal to 4.184 kilojoules (kj).

The conversion between kilocalories and kilojoules is based on the energy units used in nutrition and physics. One kcal represents the amount of energy required to raise the temperature of 1 kilogram of water by 1 degree Celsius, and this amount equals exactly 4.184 kilojoules.

Conversion Tool

Conversion Formula

The formula to convert kilocalories (kcal) to kilojoules (kj) is:

kj = kcal × 4.184

This works because 1 kilocalorie is defined as exactly 4.184 kilojoules. The multiplier 4.184 converts the energy value from the calorie unit to the joule unit, which is the SI (International System) standard for energy.

Example calculation:

• Given: 1 kcal
• Multiply: 1 × 4.184 = 4.184 kj
• Result: 1 kcal equals 4.184 kj

Conversion Example

• 5 kcal to kj:
  • Take 5 kcal.
  • Multiply by 4.184: 5 × 4.184 = 20.92 kj.
  • So, 5 kcal equals 20.92 kj.
• 10.5 kcal to kj:
  • Start with 10.5 kcal.
  • Multiply: 10.5 × 4.184 = 43.932 kj.
  • Therefore, 10.5 kcal is 43.932 kj.
• 0.75 kcal to kj:
  • Using 0.75 kcal.
  • Calculate 0.75 × 4.184 = 3.138 kj.
  • Thus, 0.75 kcal equals 3.138 kj.
• 15 kcal to kj:
  • Take 15 kcal.
  • Multiply: 15 × 4.184 = 62.76 kj.
  • Hence, 15 kcal is 62.76 kj.

Conversion Chart

This chart helps to quickly find the equivalent kilojoule value for a given kilocalorie input from -24.0 to 26.0 kcal. You can read across the row to find the kj value without calculation.

Related Conversion Questions

• How many kilojoules are in 1 kcal?
• What is the exact kj equivalent of one kilocalorie?
• Convert 1 kcal to kj with decimal precision?
• How to change 1 kcal to kilojoule unit quickly?
• Why does 1 kcal equal 4.184 kj?
• What formula is used for converting 1 kcal into kj?
• How to convert nutritional energy of 1 kcal to kj?

Conversion Definitions

kcal: Kilocalorie, also called “large calorie,” is a unit of energy measuring heat. It represents the energy needed to raise the temperature of 1 kilogram of water by 1°C at standard pressure. It is commonly used in food energy labeling and nutrition.

kj: Kilojoule is the SI unit of energy equal to 1000 joules. It measures work, heat, or energy transfer, and is widely used in scientific and nutritional contexts to quantify energy content, replacing calories in many countries.

Conversion FAQs

Is 1 kcal always equal to 4.184 kj?

Yes, by definition, 1 kilocalorie equals exactly 4.184 kilojoules. This is a fixed conversion constant, so regardless of context, the conversion factor remains the same without variation.

Can I convert kcal to kj by dividing instead of multiplying?

No, to convert from kcal to kj, you multiply by 4.184 because 1 kcal contains more energy than 1 kj. Dividing would give incorrect, smaller values, so multiplication is necessary.

Why do some nutrition labels show kj instead of kcal?

Some countries prefer the SI unit for energy, which is the kilojoule, so labels use kj to align with international standards. Both units represent energy, but kj is part of the metric system and preferred in scientific settings.

Does the energy content change when converting kcal to kj?

No, the energy content remains the same. Conversion changes only the unit of measurement, not the physical amount of energy represented.

Is the conversion factor 4.184 an approximation?

No, 4.184 kj per kcal is an exact conversion based on the defined energy to heat 1 kg of water by 1°C, used internationally in science and nutrition without approximation.