Convert joules to calories

1 J=0.239cal

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

You have

Equals

0.23901

Conversion formula

Forward

calories = joules × 0.239

Reverse

joules = calories × 4.184

Example: 10 J × 0.239 = 2.39006 cal.

About both units

From

Joule

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 →

Calorie

cal

The gram calorie (small calorie) equals 4.184 joules — the energy to raise 1 g of water by 1 °C. It is a scientific unit, distinct from the nutrition "Calorie" (kcal). Largely replaced by joules in modern science.

Real-world: Raising 1 g of water 1 °C: 1 cal. A 100 kcal snack = 100,000 small calories.

Read full calorie reference →

Joule to Calorie conversion table

Common joules to calories values for quick reference.

Joule (J)	Calorie (cal)
1 J	0.239 cal
10 J	2.39006 cal
100 J	23.9006 cal
500 J	119.503 cal
1,000 J	239.006 cal
5,000 J	1,195.03 cal
10,000 J	2,390.06 cal
50,000 J	11,950.29 cal
100,000 J	23,900.57 cal
500,000 J	119,502.87 cal

Tips & common mistakes

Quick tips

1 J = 1 N·m = 1 W·s.
1 kWh = 3,600,000 J (3.6 MJ).
For nutrition 1 kcal = 4.184 kJ.

Avoid these

Confusing joule (energy) with newton (force).
Mixing joule with watt — watt is joule per second.
Using kJ when labels call for kcal on US nutrition.

Frequently asked questions

How many calories in a joule?

One joule equals 0.239 calories.

How do I convert joules to calories?

Multiply the joule value by 0.239 to get the equivalent in calories.

What is 100 joules in calories?

100 joules equals 23.9006 calories.

Is a joule bigger than a calorie?

No. 1 joule equals 0.239 calories, so one joule is smaller.

How to convert joules to calories without a calculator?

Multiply by 0.24 for a quick estimate; use a calculator for precise results.

Related energy conversions

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