Megajoule to Gigajoule Converter
Convert Megajoule (MJ) to Gigajoule (GJ) instantly. 1 MJ = 0.001 GJ.
Energy Converter
27 units available
1 MJ = 0.001 GJ
Formula:
GJ = MJ × 0.001With your value: 1 MJ = 0.001 GJ
How big is that?
Everyday references on a logarithmic scale, all expressed in megajoule so you can sanity-check the result.
Other Megajoule to Gigajoule conversions
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 |
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 |
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.
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
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
How to Convert Megajoule to Gigajoule
To convert from Megajoule (MJ) to Gigajoule (GJ), multiply the value by 0.001.
Formula: GJ = MJ × 0.001
Reverse: MJ = GJ × 1,000
Step-by-Step Example
- Start with your value in Megajoule. For example: 5 MJ
- Multiply by the conversion factor: 5 x 0.001
- The result is: 0.005 GJ
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.
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.
Frequently Asked Questions
How many Gigajoule are in 1 Megajoule?
There are exactly 0.001 Gigajoule in 1 Megajoule. This means the conversion factor from Megajoule to Gigajoule is 0.001.
What is the formula to convert Megajoule to Gigajoule?
The formula to convert Megajoule to Gigajoule is: GJ = MJ × 0.001. For example, to convert 10 Megajoule to Gigajoule, you would multiply 10 by 0.001.
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 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 are the common uses of Megajoule?
The Megajoule is commonly used in energy calculations, engineering and science, education.
Related Energy Conversions
Cite this page
UnitConvertLab. (2026). Megajoule to Gigajoule converter. UnitConvertLab. Retrieved from https://unitconvertlab.com/convert/megajoule-to-gigajoule