How do you convert gigajoules to kilocalories?

To convert gigajoules (GJ) to kilocalories (kcal), multiply the energy in gigajoules by 239,005.73613766 (kilocalories = gigajoules × 239,005.73613766).

What is 5 gigajoules in kilocalories?

5 gigajoules (5 GJ) is equal to 1,195,028.68068833 kilocalories (1,195,028.68068833 kcal).

Which is larger, 1 gigajoule (GJ) or 1 kilocalorie (food calorie) (kcal)?

One gigajoule (GJ) is larger than one kilocalorie (food calorie) (kcal). Specifically, 1 GJ contains 239,005.73613766 kcal, whereas 1 kcal is 0.00000418 GJ.

How do I convert back from kilocalories (kcal) to gigajoules (GJ)?

To reverse the calculation from kcal to GJ, multiply your kilocalorie (food calorie) value by the inverse factor 0.00000418 (or divide by 239,005.73613766). You can also click the Swap button in the tool above to flip directions in one click.

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

For everyday comparisons and quick estimates, rounding to 2 decimal places is usually sufficient (for example, 5 GJ ≈ 1,195,028.68 kcal). For engineering, laboratory, or machining specifications, select 4 or 6 decimals—or Scientific (10ⁿ) mode—in the calculator toolbar above.

Gigajoules to Kilocalories Converter

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

Kilocalories to Gigajoules (kcal → GJ)

Convert Gigajoules to Kilocalories

Enter a value in gigajoules (GJ) to convert to kilocalories (kcal).

Value (GJ)

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Result

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1,195,028.680688336kilocalories

5 GJ = 1,195,028.680688336 kcal

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Suggested Conversions

Reference:NIST CODATA (CODATA Energy & Thermodynamic Constants)

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Gigajoule to Kilocalorie Conversion Table

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

Gigajoules (GJ)	Kilocalories (kcal)
0.0000001 GJ	0.0239006 kcal
0.0000002 GJ	0.0478011 kcal
0.0000003 GJ	0.0717017 kcal
0.0000004 GJ	0.0956023 kcal
0.0000005 GJ	0.1195029 kcal
0.0000006 GJ	0.1434034 kcal
0.0000007 GJ	0.167304 kcal
0.0000008 GJ	0.1912046 kcal
0.0000009 GJ	0.2151052 kcal
0.00000001 GJ	0.0023901 kcal

How to Convert Gigajoules to Kilocalories

To convert gigajoules to kilocalories, multiply the energy by the following conversion ratio: 239,005.7361377 kilocalories/gigajoule.

Since one gigajoule is equal to 239,005.7361377 kilocalories, you can use this simple formula to convert:

kilocalories = gigajoules × 239,005.7361377

The energy in kilocalories is equal to the energy in gigajoules multiplied by 239,005.7361377.

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

kilocalories = (5 GJ × 239,005.7361377) = 1,195,028.6806883 kcal

How Many Kilocalories Are in a Gigajoule?

There are 239,005.7361377 kilocalories in a gigajoule, which is why we use this value in the formula above.

1 GJ = 239,005.7361377 kcal|1 kcal = 0.000004184 GJ

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

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

What Is a Gigajoule?

A gigajoule is a unit of energy equal to 1,000,000,000 joules (J), the base unit for energy. Equal to 1,000,000,000 Joules, common in natural gas billing. [1]

The gigajoule is classified as an International System of Units (SI) unit of energy. Gigajoules can be abbreviated as GJ; for example, 1 gigajoule can be written as 1 GJ.

In the metric system, "giga" is the standard SI prefix for billions, or 10⁹. This makes the gigajoule (GJ) a convenient decimal multiple of the joule (J).

In practice, gigajoules (GJ) are widely used across large-scale industrial, bulk, and macro-level energy specifications within International System of Units (SI) workflows, engineering documentation, and technical data sheets.

Learn more about gigajoules 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 gigajoules (GJ) and kilocalories (kcal), keep full floating-point precision (1 GJ = 239,005.7361377 kcal; 1 kcal = 0.000004184 GJ) during intermediate calculations and round only the final kilocalorie figure to match your instrument tolerance.

More Gigajoule & Kilocalorie Conversions

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

Convert from Gigajoules

Convert to Kilocalories

Frequently Asked Questions

There are 239,005.73613766 kilocalories (kcal) in 1 gigajoule (GJ). Conversely, 1 kilocalorie (kcal) is equal to 0.00000418 gigajoules (GJ).

Energy Converter

Quick Info

Direct Factor: 1 gigajoule (GJ) equals 239,005.73613766 kilocalories (kcal).
Inverse Factor: 1 kilocalorie (food calorie) (kcal) equals 0.00000418 gigajoules (GJ).
Formula: kilocalories = gigajoules × 239,005.73613766.
Verified Precision: Anchored to official NIST SP 811 and ISO/IEC 80000 standards.

Units Comparison

Gigajoule (GJ)

Equal to 1,000,000,000 Joules, common in natural gas billing.

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

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