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Joules to Calories

One joule equals 0.239006 calories.

Calories = joules ÷ 4.184

Energy Converter

Common Conversions

Energy Examples

Household Energy

  • • Average home daily use: ~30 kWh
  • • LED bulb (10W, 1 hour): 36 kJ
  • • Microwave (1000W, 2 min): 120 kJ
  • • Electric car (100 miles): ~30 kWh

Food Energy

  • • Apple: ~350 kJ (80 kcal)
  • • Slice of bread: ~315 kJ (75 kcal)
  • • Can of soda: ~590 kJ (140 kcal)
  • • Daily intake: ~8400 kJ (2000 kcal)

Energy Unit Reference

Scientific Units

  • Joule (J): SI base unit of energy
  • Calorie (cal): Energy to heat 1g water by 1°C
  • Electron Volt (eV): Atomic scale energy
  • Erg: CGS unit (very small)

Practical Units

  • kWh: Electrical energy billing
  • BTU: Heating/cooling systems
  • Therm: Natural gas billing
  • kcal: Food energy (Calories)

Joules to Calories Conversion Table

Jcal
10.239
51.195
102.3901
5011.9503
10023.9006
500119.5029
1000239.0057
2000478.0115
41841000
50001195.0287
100002390.0574
5000011950.2868
10000023900.5736

About This Conversion

Joules to calories divides by 4.184. It is the conversion used to read a scientific or engineering energy figure in the units nutrition labels and older heating specifications use.

Outside the United States, food labels usually give kilojoules first: a 1,000 kJ portion is 239 kcal. Dividing kilojoules by 4.184 gives kilocalories directly, which is the same arithmetic one step up.

Frequently Asked Questions

How many calories is one joule?

One joule is about 0.239 calories.

How many calories is 1000 joules?

1,000 joules is about 239 small calories, or 0.239 food Calories.

How do I convert kilojoules to Calories?

Divide kilojoules by 4.184. A 1,000 kJ portion is 239 kcal.

How many joules is one food Calorie?

One food Calorie is 4,184 joules, or 4.184 kilojoules.

Worth Knowing

Calorie vs Kilocalorie

One food Calorie is one kilocalorie, equal to 1,000 small calories or 4,184 joules.