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Millijoules to Microjoules Converter

Enter the energy in millijoules below to convert it to microjoules.

Convert Millijoules to Microjoules

Enter a value in millijoules (mJ) to convert to microjoules (µJ).

Result
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5,000microjoules
5 mJ = 5,000 µJ
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Reference:NIST CODATA (CODATA Energy & Thermodynamic Constants)
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Millijoule to Microjoule Conversion Table

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

How to Convert Millijoules to Microjoules

To convert millijoules to microjoules, multiply the energy by the following conversion ratio: 1,000 microjoules/millijoule.

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

microjoules = millijoules × 1,000

The energy in microjoules is equal to the energy in millijoules multiplied by 1,000.

For example, here's how to convert 5 millijoules to microjoules using the formula above.

microjoules = (5 mJ × 1,000) = 5,000 µJ

How Many Microjoules Are in a Millijoule?

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

1 mJ = 1,000 µJ|1 µJ = 0.001 mJ

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

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

What Is a Millijoule?

A millijoule is a unit of energy equal to 1/1,000 of a joule (0.001 J). One-thousandth of a Joule. [1]

The millijoule is classified as a metric and SI-compatible unit of energy. Millijoules can be abbreviated as mJ; for example, 1 millijoule can be written as 1 mJ.

In the metric system, "milli" is the standard SI prefix for thousandths, or 10⁻³. This makes the millijoule (mJ) a convenient decimal multiple of the joule (J).

In practice, millijoules (mJ) are widely used across fine-tolerance laboratory, analytical, and micro-scale energy measurements within SI metric workflows, engineering documentation, and technical data sheets.

What Is a Microjoule?

A microjoule is a unit of energy equal to 1/1,000,000 of a joule (0.000001 J). One-millionth of a Joule. [2]

The microjoule is classified as a metric and SI-compatible unit of energy. Microjoules can be abbreviated as µJ; for example, 1 microjoule can be written as 1 µJ.

In the metric system, "micro" is the standard SI prefix for millionths, or 10⁻⁶. This makes the microjoule (µJ) a convenient decimal multiple of the joule (J).

In practice, microjoules (µJ) are widely used across fine-tolerance laboratory, analytical, and micro-scale energy measurements within SI metric workflows, engineering documentation, and technical data sheets.

When converting energy between millijoules (mJ) and microjoules (µJ), keep full floating-point precision (1 mJ = 1,000 µJ; 1 µJ = 0.001 mJ) during intermediate calculations and round only the final microjoule figure to match your instrument tolerance.

More Millijoule & Microjoule Conversions

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

Frequently Asked Questions

There are 1,000 microjoules (µJ) in 1 millijoule (mJ). Conversely, 1 microjoule (µJ) is equal to 0.001 millijoules (mJ).

References

NIST · BIPM · ISO
  1. [1]
    NIST CODATA (CODATA Energy & Thermodynamic Constants)·Energy Metrology Standard — Millijoules (mJ) to Microjoules (µJ)
    NIST CODATA Standard
  2. [2]
    NIST SP 811 (NIST SP 811 App. B.9 (Energy, Work & Heat))·Unit Specifications: Millijoule (mJ) & Microjoule (µJ)
    NIST SP 811 Specification
  3. [3]
    BIPM (Derived SI Unit: Joule (J))·Conversion Factors & Mathematical Basis (mJ to µJ)
    BIPM Reference
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