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Joules to Kilocalories Converter

Convert joules to kilocalories and kcal to joules instantly. Bidirectional energy converter with formula and common values.

Joules to Kilocalories: 1 J equals 0.000239 kcal. To convert joules to kilocalories, multiply by 0.000239 (kcal = J × 0.000239006). For example, 10 J = 0.00239 kcal.

8400 J = 2.008 kcal

kcal = J × 0.000239006

How to Convert Joules to Kilocalories

To convert from joules to kilocalories, multiply the value by 0.000239. The conversion is linear, meaning doubling the input doubles the output.

Conversion Formula

  • Joules to Kilocalories: kcal = J × 0.000239006
  • Kilocalories to Joules: J = kcal ÷ 0.000239006
Joules to Kilocalories conversion scale — a dual ruler showing 1 J equals .0002 kcal.
Joules to Kilocalories conversion scale (J to kcal).

Joules to Kilocalories Conversion Chart

Joules (J)Kilocalories (kcal)
0.12.39006e-5
0.255.97515e-5
0.50.00012
10.000239
20.000478
30.000717
50.001195
100.00239
200.00478
250.005975
500.01195
1000.023901
2500.059751
10000.239006

Understanding the Units

What is a Joule?

The joule is the SI derived unit of energy, equal to the work done by a force of one newton acting through a distance of one meter (1 J = 1 N·m = 1 W·s).

Named after James Prescott Joule (1818–1889), the English physicist who demonstrated the mechanical equivalent of heat.

Common contexts: physics, chemistry, engineering.

What is a Kilocalorie?

A kilocalorie (kcal) equals 1,000 small calories, or 4,184 joules. In nutrition, the food "Calorie" (capital C) refers to the kilocalorie.

Common contexts: nutrition (US), metabolism, food labeling.

Real-World Reference Points

Item Joules (J) Kilocalories (kcal)
Energy to lift an apple 1 m10.0002
Heart beat (resting)10.0002
AA battery (alkaline)90002.1511

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FAQ

How many kilocalories are in one joule?

One joule equals approximately 0.000239006 kilocalories. You need about 4,184 joules to make one kilocalorie.

How do I convert joules to kilocalories?

Divide the joule value by 4,184 (or multiply by 0.000239006). For example, 8,368 J ÷ 4,184 = 2.0 kcal.

How many joules are in a food Calorie?

One food Calorie (capital C) equals one kilocalorie, which equals 4,184 joules. A 200-Calorie snack contains 836,800 joules.

Why do European food labels use kilojoules?

EU regulations require energy values in kilojoules (kJ) as the primary unit, with kilocalories as optional. This follows the SI system where the joule is the standard energy unit.

How many kilocalories are in 1 joul?

1 J equals 0.000239 kcal.

How do you convert joules to kilocalories?

Multiply the joul value by 0.000239. Formula: kcal = J × 0.000239006.

How many kilocalories are in 5 joules?

5 J = 0.001195 kcal.

How do you convert kilocalories back to joules?

Use the inverse formula: J = kcal ÷ 0.000239006. For example, 1 kcal = 4183.995381 J.

What is the difference between Joul and Kilocalory?

The joule is the SI derived unit of energy, equal to the work done by a force of one newton acting through a distance of one meter (1 J = 1 N·m = 1 W·s). A kilocalorie (kcal) equals 1,000 small calories, or 4,184 joules. In nutrition, the food "Calorie" (capital C) refers to the kilocalorie.