Gigajoule to Megajoule Converter
Convert Gigajoule (GJ) to Megajoule (MJ) instantly. 1 GJ = 1,000 MJ.
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27 units available
1 GJ = 1,000 MJ
Formula:
MJ = GJ × 1,000With your value: 1 GJ = 1,000 MJ
How big is that?
Everyday references on a logarithmic scale, all expressed in gigajoule so you can sanity-check the result.
Other Gigajoule to Megajoule conversions
Gigajoule to Megajoule Conversion Table
| Gigajoule (GJ) | Megajoule (MJ) |
|---|---|
| 0.5 | 500 |
| 1 | 1,000 |
| 2 | 2,000 |
| 5 | 5,000 |
| 10 | 10,000 |
| 15 | 15,000 |
| 20 | 20,000 |
| 25 | 25,000 |
| 50 | 50,000 |
| 100 | 100,000 |
| 250 | 250,000 |
| 500 | 500,000 |
| 1000 | 1,000,000 |
Megajoule to Gigajoule Conversion Table
| Megajoule (MJ) | Gigajoule (GJ) |
|---|---|
| 0.5 | 0.0005 |
| 1 | 0.001 |
| 2 | 0.002 |
| 5 | 0.005 |
| 10 | 0.01 |
| 15 | 0.015 |
| 20 | 0.02 |
| 25 | 0.025 |
| 50 | 0.05 |
| 100 | 0.1 |
| 250 | 0.25 |
| 500 | 0.5 |
| 1000 | 1 |
Where these values come from
Every factor on this page is traced to the document that defines it. See the full provenance dataset or our methodology.
Gigajoule (GJ)
Energy
Derived from the joule (1 J = 1 kg·m²/s²). Thermochemical and IT calories, BTU and kWh are exact defined multiples.
Source: NIST Special Publication 811, Guide for the Use of the International System of Units
National Institute of Standards and Technology (US) · Reviewed 2026-07-01
Megajoule (MJ)
Energy
Derived from the joule (1 J = 1 kg·m²/s²). Thermochemical and IT calories, BTU and kWh are exact defined multiples.
Source: NIST Special Publication 811, Guide for the Use of the International System of Units
National Institute of Standards and Technology (US) · Reviewed 2026-07-01
How to Convert Gigajoule to Megajoule
To convert from Gigajoule (GJ) to Megajoule (MJ), multiply the value by 1,000.
Formula: MJ = GJ × 1,000
Reverse: GJ = MJ × 0.001
Step-by-Step Example
- Start with your value in Gigajoule. For example: 5 GJ
- Multiply by the conversion factor: 5 x 1,000
- The result is: 5,000 MJ
About Gigajoule
The gigajoule (GJ) is a unit of energy and work. One gigajoule equals 1.000000 × 10^+9 joules. UnitConvertLab converts it against every other energy unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.
Common uses: energy calculations, engineering and science, education.
About Megajoule
The megajoule (MJ) is a unit of energy and work. One megajoule equals 1.000000 × 10^+6 joules. UnitConvertLab converts it against every other energy unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.
Common uses: energy calculations, engineering and science, education.
Frequently Asked Questions
How many Megajoule are in 1 Gigajoule?
There are exactly 1,000 Megajoule in 1 Gigajoule. This means the conversion factor from Gigajoule to Megajoule is 1,000.
What is the formula to convert Gigajoule to Megajoule?
The formula to convert Gigajoule to Megajoule is: MJ = GJ × 1,000. For example, to convert 10 Gigajoule to Megajoule, you would multiply 10 by 1,000.
What is a Gigajoule?
The gigajoule (GJ) is a unit of energy and work. One gigajoule equals 1.000000 × 10^+9 joules. UnitConvertLab converts it against every other energy unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.
What is a Megajoule?
The megajoule (MJ) is a unit of energy and work. One megajoule equals 1.000000 × 10^+6 joules. UnitConvertLab converts it against every other energy unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.
What are the common uses of Gigajoule?
The Gigajoule is commonly used in energy calculations, engineering and science, education.
Related Energy Conversions
Cite this page
UnitConvertLab. (2026). Gigajoule to Megajoule converter. UnitConvertLab. Retrieved from https://unitconvertlab.com/convert/gigajoule-to-megajoule