How do you convert millijoules to kilocalories?

To convert millijoules (mJ) to kilocalories (kcal), multiply the energy in millijoules by 2.390057e-7 (kilocalories = millijoules × 2.390057e-7).

What is 5 millijoules in kilocalories?

5 millijoules (5 mJ) is equal to 0.00000119 kilocalories (0.00000119 kcal).

Which is larger, 1 millijoule (mJ) or 1 kilocalorie (food calorie) (kcal)?

One kilocalorie (food calorie) (kcal) is larger than one millijoule (mJ). Specifically, 1 kcal equals 4,184,000 mJ, while 1 mJ is 2.390057e-7 kcal.

How do I convert back from kilocalories (kcal) to millijoules (mJ)?

To reverse the calculation from kcal to mJ, multiply your kilocalorie (food calorie) value by the inverse factor 4,184,000 (or divide by 2.390057e-7). You can also click the Swap button in the tool above to flip directions in one click.

How many decimal places should I round mJ to kcal results to?

For everyday comparisons and quick estimates, rounding to 2 decimal places is usually sufficient (for example, 5 mJ ≈ 0.00 kcal). For engineering, laboratory, or machining specifications, select 4 or 6 decimals—or Scientific (10ⁿ) mode—in the calculator toolbar above.

Millijoules to Kilocalories Converter

Enter the energy in millijoules below to convert it to kilocalories.

Kilocalories to Millijoules (kcal → mJ)

Convert Millijoules to Kilocalories

Enter a value in millijoules (mJ) to convert to kilocalories (kcal).

Value (mJ)

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Result

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0.000001195kilocalories

5 mJ = 0.000001195 kcal

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Suggested Conversions

Reference:NIST CODATA (CODATA Energy & Thermodynamic Constants)

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Millijoule to Kilocalorie Conversion Table

Table showing various millijoule measurements converted to kilocalories. Click any preset value or arrow to load it into the converter.

Millijoules (mJ)	Kilocalories (kcal)
1 mJ	0.000000239 kcal
10 mJ	0.00000239 kcal
100 mJ	0.000023901 kcal
1,000 mJ	0.000239006 kcal
10,000 mJ	0.0023901 kcal
100,000 mJ	0.0239006 kcal
1,000,000 mJ	0.2390057 kcal
5,000,000 mJ	1.1950287 kcal
10,000,000 mJ	2.3900574 kcal
25,400,000 mJ	6.0707457 kcal

How to Convert Millijoules to Kilocalories

To convert millijoules to kilocalories, multiply the energy by the following conversion ratio: 0.000000239 kilocalories/millijoule.

Since one millijoule is equal to 0.000000239 kilocalories, you can use this simple formula to convert:

kilocalories = millijoules × 0.000000239

The energy in kilocalories is equal to the energy in millijoules multiplied by 0.000000239.

For example, here's how to convert 5 millijoules to kilocalories using the formula above.

kilocalories = (5 mJ × 0.000000239) = 0.000001195 kcal

How Many Kilocalories Are in a Millijoule?

There are 0.000000239 kilocalories in a millijoule, which is why we use this value in the formula above.

1 mJ = 0.000000239 kcal|1 kcal = 4,184,000 mJ

Our millijoule to kilocalorie calculator automatically converts your energy measurements with full decimal and scientific precision across US customary, imperial, and SI metric standards.

Millijoules and kilocalories are both units used to measure energy. Keep reading to learn more about each unit.

What Is a Millijoule?

A millijoule is a unit of energy equal to 1/1,000 of a joule (0.001 J). One-thousandth of a Joule. [1]

The millijoule is classified as a metric and SI-compatible unit of energy. Millijoules can be abbreviated as mJ; for example, 1 millijoule can be written as 1 mJ.

In the metric system, "milli" is the standard SI prefix for thousandths, or 10⁻³. This makes the millijoule (mJ) a convenient decimal multiple of the joule (J).

In practice, millijoules (mJ) are widely used across fine-tolerance laboratory, analytical, and micro-scale energy measurements within SI metric workflows, engineering documentation, and technical data sheets.

Learn more about millijoules in our Energy Converter.

What Is a Kilocalorie?

A kilocalorie is a unit of energy equal to 4,184 joules (J), the base unit for energy. Dietary Calorie equal to 1,000 small calories (4,184 Joules). [2]

The kilocalorie is classified as a standard unit of energy. Kilocalories can be abbreviated as kcal; for example, 1 kilocalorie can be written as 1 kcal.

In the metric system, "kilo" is the standard SI prefix for thousands, or 10³. This makes the kilocalorie (kcal) a convenient decimal multiple of the calorie (cal).

In practice, kilocalories (kcal) are widely used across large-scale industrial, bulk, and macro-level energy specifications within international standard workflows, engineering documentation, and technical data sheets.

Learn more about kilocalories in our Energy Converter.

When converting energy between millijoules (mJ) and kilocalories (kcal), keep full floating-point precision (1 mJ = 0.000000239 kcal; 1 kcal = 4,184,000 mJ) during intermediate calculations and round only the final kilocalorie figure to match your instrument tolerance.

More Millijoule & Kilocalorie Conversions

Need to calculate in the opposite direction? Use our kilocalories to millijoules calculator to switch your starting unit immediately. You can also explore related tools such as converting kilocalories to millijoules, converting calories to kilocalories, or converting kilojoules to kilocalories.

Convert from Millijoules

Convert to Kilocalories

Frequently Asked Questions

There are 2.390057e-7 kilocalories (kcal) in 1 millijoule (mJ). Conversely, 1 kilocalorie (kcal) is equal to 4,184,000 millijoules (mJ).

Energy Converter

Quick Info

Direct Factor: 1 millijoule (mJ) equals 2.390057e-7 kilocalories (kcal).
Inverse Factor: 1 kilocalorie (food calorie) (kcal) equals 4,184,000 millijoules (mJ).
Formula: kilocalories = millijoules × 2.390057e-7.
Verified Precision: Anchored to official NIST SP 811 and ISO/IEC 80000 standards.

Units Comparison

Millijoule (mJ)

One-thousandth of a Joule.

Kilocalorie (Food Calorie) (kcal)

Dietary Calorie equal to 1,000 small calories (4,184 Joules).

Joule (J)

Coherent SI unit of energy and work (1 W·s = 1 N·m).

References

[1]NIST CODATA · CODATA Energy & Thermodynamic Constants
Source
[2]NIST SP 811 · NIST SP 811 App. B.9 (Energy, Work & Heat)
Source
[3]BIPM · Derived SI Unit: Joule (J)
Source

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References

NIST · BIPM · ISO

[1]
NIST CODATA (CODATA Energy & Thermodynamic Constants)·Energy Metrology Standard — Millijoules (mJ) to Kilocalories (kcal)
NIST CODATA Standard
[2]
NIST SP 811 (NIST SP 811 App. B.9 (Energy, Work & Heat))·Unit Specifications: Millijoule (mJ) & Kilocalorie (Food Calorie) (kcal)
NIST SP 811 Specification
[3]
BIPM (Derived SI Unit: Joule (J))·Conversion Factors & Mathematical Basis (mJ to kcal)
BIPM Reference

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