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Energy

Convert kilocalories to joules

1 kcal=4,184J

Use the converter below to change any kilocalories value into joules instantly — with formula, conversion table, and real-world examples.

4,184

Conversion formula

Forward
joules = kilocalories × 4,184
Reverse
kilocalories = joules × 0.000239

Example: 10 kcal × 4,184 = 41,840 J.

About both units

From

Kilocalorie

kcal

The kilocalorie equals 1000 small calories or 4184 joules. This is the nutrition "Calorie" (capital C in some US labels). EU and UK labels always say kcal; US labels say Calories. Adult daily intake is about 2000 kcal.

Real-world: Adult daily intake: ~2000 kcal. Banana: 90 kcal. Big Mac: 550 kcal. 30 min running: ~300 kcal burned.
Read full kilocalorie reference →
To

Joule

J

The joule is the SI unit of energy, work and heat. Defined as one newton-metre or one watt-second. Named after James Prescott Joule who demonstrated the mechanical equivalent of heat. Lifting a 100 g apple 1 metre requires about 1 J.

Real-world: Lifting a 100 g apple 1 m: ≈ 1 J. 100 kcal snack: 418,400 J. Hand grenade: ~650 kJ.
Read full joule reference →

Kilocalorie to Joule conversion table

Common kilocalories to joules values for quick reference.

Kilocalorie (kcal)Joule (J)
1 kcal4,184 J
10 kcal41,840 J
100 kcal418,400 J
500 kcal2,092,000 J
1,000 kcal4,184,000 J
5,000 kcal20,920,000 J
10,000 kcal41,840,000 J
50,000 kcal209,200,000 J
100,000 kcal418,400,000 J
500,000 kcal2,092,000,000 J

Tips & common mistakes

Quick tips

  • 1 kcal = 4.184 kJ.
  • US "Calorie" (with capital C) = 1 kcal.
  • Apps and smartwatches track active energy in kcal.

Avoid these

  • Reading food "Calories" as gram calories — factor of 1000 off.
  • Treating all calorie values as comparable — macros (fat, protein, carb) differ in energy density.
  • Counting kcal without portion size leads to underestimates.

Frequently asked questions

How many joules in a kilocalorie?
One kilocalorie equals 4,184 joules.
How do I convert kilocalories to joules?
Multiply the kilocalorie value by 4,184 to get the equivalent in joules.
What is 100 kilocalories in joules?
100 kilocalories equals 418,400 joules.
Is a kilocalorie bigger than a joule?
Yes. 1 kilocalorie equals 4,184 joules, so one kilocalorie is larger.
How to convert kilocalories to joules without a calculator?
Multiply by 4,184 for a quick estimate; use a calculator for precise results.

Related energy conversions

📊 See full comparison matrix →

More from Kilocalorie

kcal → kJ
1 = 4.184 kJ
kcal → MJ
1 = 0.004184 MJ
kcal → kWh
1 = 0.001162 kWh
kcal → Wh
1 = 1.16222 Wh
kcal → cal
1 = 1,000 cal
kcal → BTU
1 = 3.96567 BTU
kcal → eV
1 = 2.6114e22 eV
kcal → thm
1 = 3.9657e-5 thm

More to Joule

kJ → J
1 = 1,000 J
MJ → J
1 = 1,000,000 J
kWh → J
1 = 3,600,000 J
Wh → J
1 = 3,600 J
cal → J
1 = 4.184 J
BTU → J
1 = 1,055.06 J
eV → J
1 = 1.6022e-19 J
thm → J
1 = 105,505,585.3 J

Conversions in other categories

WeightKilogram → PoundLengthKilometer → MileTemperatureCelsius → FahrenheitVolumeLiter → US GallonAreaSquare Meter → Square FootSpeedKilometer per Hour → Mile per HourPressureBar → Pound per Square InchPowerKilowatt → Mechanical Horsepower