UnitsConverter

Megajoule to Gigajoule Converter

Convert megajoules to gigajoules with our free online energy converter.

Quick Answer

1 Megajoule = 0.001 gigajoules

Formula: Megajoule × conversion factor = Gigajoule

Use the calculator below for instant, accurate conversions.

Our Accuracy Guarantee

All conversion formulas on UnitsConverter.io have been verified against NIST (National Institute of Standards and Technology) guidelines and international SI standards. Our calculations are accurate to 10 decimal places for standard conversions and use arbitrary precision arithmetic for astronomical units.

Last verified: February 2026Reviewed by: Sam Mathew, Software Engineer

Megajoule to Gigajoule Calculator

How to Use the Megajoule to Gigajoule Calculator:

  1. Enter the value you want to convert in the 'From' field (Megajoule).
  2. The converted value in Gigajoule will appear automatically in the 'To' field.
  3. Use the dropdown menus to select different units within the Energy category.
  4. Click the swap button (⇌) to reverse the conversion direction.
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How to Convert Megajoule to Gigajoule: Step-by-Step Guide

Converting Megajoule to Gigajoule involves multiplying the value by a specific conversion factor, as shown in the formula below.

Formula:

GJ = MJ × 0.001

Example Calculation:

1 MJ = 0.001 GJ

Disclaimer: For Reference Only

These conversion results are provided for informational purposes only. While we strive for accuracy, we make no guarantees regarding the precision of these results, especially for conversions involving extremely large or small numbers which may be subject to the inherent limitations of standard computer floating-point arithmetic.

Not for professional use. Results should be verified before use in any critical application. View our Terms of Service for more information.

Need to convert to other energy units?

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📋 Unit Symbols

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What is a Megajoule and a Gigajoule?

1 MJ = 1,000,000 J = 1,000 kJ = 0.278 kWh = 948 BTU = 239 kcal

1 GJ = 1,000,000,000 joules (J)

Note: The Megajoule is part of the imperial/US customary system, primarily used in the US, UK, and Canada for everyday measurements. The Gigajoule belongs to the imperial/US customary system.

Common Uses and Applications: megajoules vs gigajoules

Explore the typical applications for both Megajoule (imperial/US) and Gigajoule (imperial/US) to understand their common contexts.

Common Uses for megajoules

Automotive: Crash test energy, fuel energy content specifications. Energy: Natural gas content, biomass energy, fuel comparisons. Manufacturing: Industrial heating, process energy requirements. Nutrition: Large-scale food production energy calculations.

When to Use gigajoules

Used in physics, engineering, energy systems, and scientific calculations where this energy scale is appropriate for the application.

Additional Unit Information

About Megajoule (MJ)

How do I convert MJ to kWh?

Formula: kWh = MJ × 0.278 (or MJ ÷ 3.6)

Examples:

  • 1 MJ = 0.278 kWh
  • 10 MJ = 2.78 kWh
  • 100 MJ = 27.8 kWh
  • 3.6 MJ = 1 kWh

MJ to kWh converter →

How many MJ in a liter of gasoline?

1 liter of gasoline ≈ 32 MJ (varies slightly by formulation)

Other fuels:

  • Diesel: ~36 MJ/liter (higher energy density)
  • E85 ethanol: ~24 MJ/liter
  • LPG: ~26 MJ/liter
  • Jet fuel: ~35 MJ/liter

How do I convert MJ to joules?

Formula: J = MJ × 1,000,000

Examples:

  • 1 MJ = 1,000,000 J
  • 0.1 MJ = 100,000 J = 100 kJ
  • 10 MJ = 10,000,000 J = 10,000 kJ

MJ to Joules converter →

How many MJ does a car use per 100 km?

Typical fuel consumption:

  • Small car (5 L/100km): ~160 MJ/100km
  • Medium car (8 L/100km): ~256 MJ/100km
  • SUV (12 L/100km): ~384 MJ/100km
  • Electric car (20 kWh/100km): ~72 MJ/100km

Gasoline cars use roughly 2-3x more energy than EVs due to engine efficiency losses.

About Gigajoule (GJ)

How do I convert GJ to joules?

Formula: J = GJ × 1,000,000,000

Gigajoule to Joules converter →

How do I convert GJ to kWh?

To convert to kilowatt-hours, first convert to joules, then divide by 3,600,000.

Gigajoule to kWh converter →

What is Gigajoule used for?

Gigajoule is used in contexts where the energy scale makes it convenient compared to very large or very small joule values. It provides a practical measurement unit for specific applications.

Conversion Table: Megajoule to Gigajoule

Megajoule (MJ)Gigajoule (GJ)
0.50.001
10.001
1.50.002
20.002
50.005
100.01
250.025
500.05
1000.1
2500.25
5000.5
1,0001

People Also Ask

How do I convert Megajoule to Gigajoule?

To convert Megajoule to Gigajoule, enter the value in Megajoule in the calculator above. The conversion will happen automatically. Use our free online converter for instant and accurate results. You can also visit our energy converter page to convert between other units in this category.

Learn more →

What is the conversion factor from Megajoule to Gigajoule?

The conversion factor depends on the specific relationship between Megajoule and Gigajoule. You can find the exact conversion formula and factor on this page. Our calculator handles all calculations automatically. See the conversion table above for common values.

Can I convert Gigajoule back to Megajoule?

Yes! You can easily convert Gigajoule back to Megajoule by using the swap button (⇌) in the calculator above, or by visiting our Gigajoule to Megajoule converter page. You can also explore other energy conversions on our category page.

Learn more →

What are common uses for Megajoule and Gigajoule?

Megajoule and Gigajoule are both standard units used in energy measurements. They are commonly used in various applications including engineering, construction, cooking, and scientific research. Browse our energy converter for more conversion options.

For more energy conversion questions, visit our FAQ page or explore our conversion guides.

Helpful Conversion Guides

Learn more about unit conversion with our comprehensive guides:

📚 How to Convert Units

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🔢 Conversion Formulas

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⚖️ Metric vs Imperial

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⚠️ Common Mistakes

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All Energy Conversions

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Other Energy Units and Conversions

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Verified Against Authority Standards

All conversion formulas have been verified against international standards and authoritative sources to ensure maximum accuracy and reliability.

NIST Reference on Constants, Units and Uncertainty

National Institute of Standards and Technology — Fundamental physical constants and unit conversions

BIPM SI Units

Bureau International des Poids et Mesures — International System of Units (SI) definitions and standards

ISO 80000

International Organization for Standardization — Quantities and units international standards series

Last verified: February 19, 2026