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Single conversion
To convert from Joule (J) to Megajoule (MJ), use the following formula:
Let's convert 5 Joule (J) to Megajoule (MJ).
Using the formula:
Therefore, 5 Joule (J) is equal to Megajoule (MJ).
Here are some quick reference conversions from Joule (J) to Megajoule (MJ):
| Joules | Megajoules |
|---|---|
| 0.000001 J | MJ |
| 0.001 J | MJ |
| 0.1 J | MJ |
| 1 J | MJ |
| 2 J | MJ |
| 3 J | MJ |
| 4 J | MJ |
| 5 J | MJ |
| 6 J | MJ |
| 7 J | MJ |
| 8 J | MJ |
| 9 J | MJ |
| 10 J | MJ |
| 20 J | MJ |
| 30 J | MJ |
| 40 J | MJ |
| 50 J | MJ |
| 100 J | MJ |
| 1000 J | MJ |
| 10000 J | MJ |
For all Energy converters, choose units using the From/To dropdowns above.
The joule (J), as part of the International System of Units (SI), is a fundamental unit used to measure energy.
Whether you're discussing the electricity that powers your home, the work done by a machine, or the energy you get from food, the joule is the universal standard.
Key Takeaways:
A joule (J) represents the amount of work done when a force of one newton moves an object by one meter.
This is formally expressed as:
1 J = 1 N·m
To make that simpler, think of it this way: lifting a small apple (which weighs about one newton) one meter straight up requires about one joule of energy.
This direct link between force, distance, and energy makes the joule a cornerstone unit in physics and engineering.
It's easy to mix up joules and watts, but the key difference is time.
Specifically, one watt is equal to one joule of energy transferred per second (1 W = 1 J/s).
For example, a 100-watt light bulb uses 100 joules of electrical energy every second it is on.
While many food labels use calories (specifically kilocalories, or kcal), the official SI unit for food energy is the joule.
The conversion is straightforward:
1 food calorie (kcal) ≈ 4,184 joules or 4.184 kilojoules (kJ)
Using joules and kilojoules (kJ) provides a universal, scientific standard for measuring the energy we get from food. This is why you will often see "kJ" on nutrition labels in many parts of the world.
Ever looked at a food label outside the US or heard about the energy of a lightning bolt and seen the term 'megajoule' or 'MJ'?
What exactly is it?
In this simple guide, we'll break down what a megajoule is, how big it is, and where you'll see it used in everyday life and science.
A Megajoule (MJ) is a unit of energy in the International System of Units (SI), equal to one million Joules (106 J).
The plural form is Megajoules.
To visualize the energy in a single megajoule, it helps to use a powerful real-world comparison.
One megajoule (1 MJ) is roughly the same as the kinetic energy of a one-tonne car traveling at 160 km/h (about 100 mph).
This comparison shows just how much energy a single megajoule represents, making it a key unit for measuring large energy transfers in fields like physics and engineering.
In many countries, including Australia and New Zealand, the megajoule (MJ) and kilojoule (kJ) are the standard units on nutritional labels to measure the energy content of food, instead of Calories (kcal).
To understand these labels, it's helpful to know the conversion:
One megajoule (MJ) is equal to approximately 239 food Calories (kcal).
This makes the MJ a critical unit for international dietary and health management.
The megajoule is a common unit for quantifying large-scale energy events and outputs in science and technology.
For example: