Convert Joules (J) to Calories (thermochemical) (cal)

1 joule equals 0.239006 calories (thermochemical).

Formula: cal = J × 0.239006

Joule to Calorie (thermochemical) Converter

What Is a Joule?

The joule (J) is the SI unit of energy, defined as 1 kg·m²/s². It is the fundamental energy unit in all scientific contexts.

What Is a Calorie (Thermochemical)?

The thermochemical calorie (cal_th) equals exactly 4.184 joules. It is used in chemistry and physics for heat measurements. Not to be confused with the nutritional Calorie (= 1,000 cal_th).

Joule to Calorie (Thermochemical) Formula

The conversion formula is:

calories (thermo) = joules ÷ 4.184 exact

Exact: 1 cal_th = 4.184 J (defined by the International Committee on Weights and Measures).

Worked Example

Convert 100 joule (100 joules of heat):

Calculate: 100 → 23.9 calorie (thermochemical)

Common Use Cases

This conversion appears regularly in:

Chemistry and thermodynamics: Reaction enthalpies, bond energies, and heat of formation values historically published in calories must be converted to joules for modern SI-compliant calculations. Many reference tables still list values in cal/mol alongside kJ/mol.
Calorimetry experiments: Laboratory calorimeters measure heat transfer. While the instrument output may be calibrated in joules, results are often reported or compared with literature values in calories, especially in educational settings.
Physics education: Textbooks introducing thermodynamics teach the calorie as the historical heat unit. Students routinely convert between joules and calories to solve problems and understand the mechanical equivalent of heat.
Material science: Specific heat capacity values for materials are sometimes tabulated in cal/(g·°C) in older references. Converting these to J/(g·°C) requires the joule-to-calorie factor for accurate modern engineering calculations.

Frequently Asked Questions

What is the difference between thermochemical and nutritional calories?

The thermochemical calorie (cal) equals 4.184 J and is the "small calorie" used in science. The nutritional Calorie (Cal or kcal) equals 4,184 J — exactly 1,000 thermochemical calories. Food labels use the large Calorie. When a chemistry problem says "calorie" without qualification, it typically means the thermochemical (small) calorie.

Why is the conversion factor exactly 4.184?

The thermochemical calorie is defined as exactly 4.184 joules by international agreement (the Fifth International Conference on the Properties of Steam, 1956). This is a definition, not a measurement, so the conversion is exact with no rounding error.

Are there other types of calories?

Yes. The main variants are: the thermochemical calorie (4.184 J, used in chemistry), the International Table calorie (4.1868 J, used in engineering steam tables), and the mean calorie (4.190 J, based on heating water from 0 to 100°C). The differences are small but matter in precision work.

Who established the relationship between joules and calories?

James Prescott Joule determined the mechanical equivalent of heat through his famous paddle-wheel experiments in the 1840s, finding that approximately 4.2 joules of mechanical work produce 1 calorie of heat. This groundbreaking result unified mechanics and thermodynamics and led to the first law of thermodynamics.

Common Joule to Calorie (thermochemical) Conversions

Joule to Calorie (thermochemical) (Part 1)

Joule	Calorie (thermochemical)	Actions
1 joule	0.239006 calories (thermochemical)
100 Joules	23.9006 calories (thermochemical)
1000 Joules	239.006 calories (thermochemical)

Joule to Calorie (thermochemical) (Part 2)

Joule	Calorie (thermochemical)	Actions
4184 Joules	1000 calories (thermochemical)
10000 Joules	2390.06 calories (thermochemical)
100000 Joules	23900.6 calories (thermochemical)

Joules to calories (thermochemical) Conversion Table

Reference table with common joules to calories (thermochemical) conversions. All values calculated with high precision.

Joules to Calories (thermochemical) Table
0.001 to 5

Joules	Calories (thermochemical)	Actions
0.001 J	0.000239006 cal
0.0025 J	0.000597514 cal
0.005 J	0.00119503 cal
0.01 J	0.00239006 cal
0.025 J	0.00597514 cal
0.05 J	0.0119503 cal
0.1 J	0.0239006 cal
14 J	0.0597514 cal
12 J	0.119503 cal
1 J	0.239006 cal
2 12 J	0.597514 cal
5 J	1.19503 cal

Joules to Calories (thermochemical) Table
10 to 1000000

Joules	Calories (thermochemical)	Actions
10 J	2.39006 cal
25 J	5.97514 cal
50 J	11.9503 cal
100 J	23.9006 cal
250 J	59.7514 cal
500 J	119.503 cal
1000 J	239.006 cal
2500 J	597.514 cal
5000 J	1195.03 cal
10000 J	2390.06 cal
25000 J	5975.14 cal
50000 J	11950.3 cal
100000 J	23900.6 cal
250000 J	59751.4 cal
500000 J	119503 cal
1000000 J	239006 cal

Calories (thermochemical) to Joules Table
0.0001 to 12

Calories (thermochemical)	Joules	Actions
0.0001 cal	0.0004184 J
0.00025 cal	0.001046 J
0.0005 cal	0.002092 J
0.001 cal	0.004184 J
0.0025 cal	0.01046 J
0.005 cal	0.02092 J
0.01 cal	0.04184 J
0.025 cal	0.1046 J
0.05 cal	0.2092 J
0.1 cal	0.4184 J
14 cal	1.046 J
12 cal	2.092 J

Calories (thermochemical) to Joules Table
1 to 100000

Calories (thermochemical)	Joules	Actions
1 cal	4.184 J
2 12 cal	10.46 J
5 cal	20.92 J
10 cal	41.84 J
25 cal	104.6 J
50 cal	209.2 J
100 cal	418.4 J
250 cal	1046 J
500 cal	2092 J
1000 cal	4184 J
2500 cal	10460 J
5000 cal	20920 J
10000 cal	41840 J
25000 cal	104600 J
50000 cal	209200 J
100000 cal	418400 J

Looking for the reverse? Convert Calorie (thermochemical) to Joule

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Conversion factors verified against NIST, BIPM, ISO 80000-4 1 cal_IT = 4.1868 J by definition (BIPM/ITS-90). Last reviewed: April 2026

By Adilson Fernandes

Reviewed by Tiago Fernandes

All unit conversions on CoolConversion use conversion factors defined or documented by internationally recognised standards bodies (such as ISO and NIST), including both SI and non-SI units.