How do you convert megajoules to joules?

To convert megajoules (MJ) to joules (J), multiply the energy in megajoules by 1,000,000 (joules = megajoules × 1,000,000).

What is 5 megajoules in joules?

5 megajoules (5 MJ) is equal to 5,000,000 joules (5,000,000 J).

Which is larger, 1 megajoule (MJ) or 1 joule (J)?

One megajoule (MJ) is larger than one joule (J). Specifically, 1 MJ contains 1,000,000 J, whereas 1 J is 0.000001 MJ.

How do I convert back from joules (J) to megajoules (MJ)?

To reverse the calculation from J to MJ, multiply your joule value by the inverse factor 0.000001 (or divide by 1,000,000). You can also click the Swap button in the tool above to flip directions in one click.

How many decimal places should I round MJ to J results to?

For everyday comparisons and quick estimates, rounding to 2 decimal places is usually sufficient (for example, 5 MJ ≈ 5,000,000.00 J). For engineering, laboratory, or machining specifications, select 4 or 6 decimals—or Scientific (10ⁿ) mode—in the calculator toolbar above.

Megajoules to Joules Converter

Enter the energy in megajoules below to convert it to joules.

Joules to Megajoules (J → MJ)

Convert Megajoules to Joules

Enter a value in megajoules (MJ) to convert to joules (J).

Value (MJ)

From

Result

•

5,000,000joules

5 MJ = 5,000,000 J

Result updates automatically

Get Widget

Suggested Conversions

Reference:NIST CODATA (CODATA Energy & Thermodynamic Constants)

[1–3] ↓

Megajoule to Joule Conversion Table

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

Megajoules (MJ)	Joules (J)
0.0000001 MJ	0.1 J
0.0000002 MJ	0.2 J
0.0000003 MJ	0.3 J
0.0000004 MJ	0.4 J
0.0000005 MJ	0.5 J
0.0000006 MJ	0.6 J
0.0000007 MJ	0.7 J
0.0000008 MJ	0.8 J
0.0000009 MJ	0.9 J
0.00000001 MJ	0.01 J

How to Convert Megajoules to Joules

To convert megajoules to joules, multiply the energy by the following conversion ratio: 1,000,000 joules/megajoule.

Since one megajoule is equal to 1,000,000 joules, you can use this simple formula to convert:

joules = megajoules × 1,000,000

The energy in joules is equal to the energy in megajoules multiplied by 1,000,000.

For example, here's how to convert 5 megajoules to joules using the formula above.

joules = (5 MJ × 1,000,000) = 5,000,000 J

How Many Joules Are in a Megajoule?

There are 1,000,000 joules in a megajoule, which is why we use this value in the formula above.

1 MJ = 1,000,000 J|1 J = 0.000001 MJ

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

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

What Is a Megajoule?

A megajoule is a unit of energy equal to 1,000,000 joules (J), the base unit for energy. Equal to 1,000,000 Joules. [1]

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

In the metric system, "mega" is the standard SI prefix for millions, or 10⁶. This makes the megajoule (MJ) a convenient decimal multiple of the joule (J).

In practice, megajoules (MJ) 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 megajoules in our Energy Converter.

What Is a Joule?

Coherent SI unit of energy and work (1 W·s = 1 N·m). It serves as a primary reference unit for measuring energy across scientific and practical applications. [2]

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

As the primary coherent reference unit for energy in this category, all other energy units are mathematically anchored to the joule (J).

In practice, joules (J) are widely used across standard energy applications within International System of Units (SI) workflows, engineering documentation, and technical data sheets.

Learn more about joules in our Energy Converter.

When converting energy between megajoules (MJ) and joules (J), keep full floating-point precision (1 MJ = 1,000,000 J; 1 J = 0.000001 MJ) during intermediate calculations and round only the final joule figure to match your instrument tolerance.

More Megajoule & Joule Conversions

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

Convert from Megajoules

Convert to Joules

Frequently Asked Questions

There are 1,000,000 joules (J) in 1 megajoule (MJ). Conversely, 1 joule (J) is equal to 0.000001 megajoules (MJ).

Energy Converter

Quick Info

Direct Factor: 1 megajoule (MJ) equals 1,000,000 joules (J).
Inverse Factor: 1 joule (J) equals 0.000001 megajoules (MJ).
Formula: joules = megajoules × 1,000,000.
Verified Precision: Anchored to official NIST SP 811 and ISO/IEC 80000 standards.

Units Comparison

Megajoule (MJ)

Equal to 1,000,000 Joules.

Joule (J)

Coherent SI unit of energy and work (1 W·s = 1 N·m).

Kilojoule (kJ)

Equal to 1,000 Joules.

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

Related Categories

Add This Calculator to Your Site

Free HTML widget · 4 embed formats

Embed the interactive Megajoules to Joules converter on your blog, classroom, or documentation page.

Customize & Get Embed Code

References

NIST · BIPM · ISO

[1]
NIST CODATA (CODATA Energy & Thermodynamic Constants)·Energy Metrology Standard — Megajoules (MJ) to Joules (J)
NIST CODATA Standard
[2]
NIST SP 811 (NIST SP 811 App. B.9 (Energy, Work & Heat))·Unit Specifications: Megajoule (MJ) & Joule (J)
NIST SP 811 Specification
[3]
BIPM (Derived SI Unit: Joule (J))·Conversion Factors & Mathematical Basis (MJ to J)
BIPM Reference

Measurement Navigator78 Categories9 Scientific Domains

Browse All 78 Measurement Categories

A–Z Directory →Sitemap

Common ConvertersEveryday metric, imperial, and US customary converters for length, weight, volume, temperature, area, pressure, energy, speed, time, and data.