Energy Converter

Convert between chemical, electrical and physical energy units.

Energy
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Related Conversions
1 kcal to kJ 5 kcal to kJ 64.8 kcal to kJ 72.9 kcal to kJ 89.1 kcal to kJ 97.2 kcal to kJ 100 kcal to kJ 324 kcal to kJ 810 kcal to kJ 1,000 kcal to kJ 5,000 kcal to kJ 100,000 kcal to kJ
Reverse Conversions
1 kJ to kcal 5 kJ to kcal 10 kJ to kcal 64.8 kJ to kcal 89.1 kJ to kcal 97.2 kJ to kcal 130 kJ to kcal 194 kJ to kcal 810 kJ to kcal 1,620 kJ to kcal 2,500 kJ to kcal 50,000 kJ to kcal
More Energy Conversions
100 J to cal 1 GJ to kWh 1 GJ to MJ 1 MJ to BTU 100 kJ to kcal 1 MJ to kWh 2 GJ to MJ 2 MJ to BTU 250 cal to J 1 kWh to cal

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Popular Conversions

Kilowatt-Hours to Megajoules Megajoules to Kilowatt-Hours Joules to Calories Kilocalories to Kilojoules British Thermal Units to Joules Watt-Hours to Joules

Common Benchmarks

AA battery 10 kJ
Gasoline liter 34 MJ
100 W bulb for 1 hour 0.1 kWh
Match stick 1 kJ
Cup of coffee 5 kJ
Laptop full charge 200 kJ

Formula

kJ = kcal × 4.184

Example

Example: convert 81 kilocalories to kilojoules.

81 kcal = 338.904 kJ

Conversion table

kilocalories (kcal) kilojoules (kJ)
1 kcal 4.184 kJ
2 kcal 8.368 kJ
5 kcal 20.92 kJ
10 kcal 41.84 kJ
20 kcal 83.68 kJ
50 kcal 209.2 kJ
100 kcal 418.4 kJ

Explanation

These are both units.

How to convert kilocalories to kilojoules

  1. Start with the value in kilocalories (kcal).
  2. Multiply it by 4.184.
  3. The result is the measurement in kilojoules (kJ).

Example: 81 kcal → 338.904 kJ

Frequently Asked Questions

How much is 81 kilocalories in kilojoules?

81 kilocalories equals 338.904 kilojoules.

How many kilojoules is 1 kilocalorie?

1 kilocalorie equals 4.184 kilojoules.

How many kilocalories is 1 kilojoule?

1 kilojoule equals 0.239005736138 kilocalories.

What is the difference between kilocalories and kilojoules?

Both measure energy in SI. The main difference is usually scale: some units are convenient for smaller values, while others are used to express larger values more practically.

Where are kilocalories and kilojoules used?

They are used in physics and engineering to measure work, energy, and heat; the most practical unit depends on the magnitude.

Why does 1 kilocalorie equal 4.184 kilojoules?

Because the units are defined with a fixed relationship. To convert kilocalories to kilojoules, multiply by that factor.