Last updated: June 06, 2025

Ohm (Ω) to Milliohm (mΩ) Converter

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Ohms to Milliohms (Ω to mΩ) Converter

This article will show how to convert electrical resistance measurement units from ohms (Ω) to milliohms (mΩ). We will cover essential definitions, provide examples, share relevant formulas, and present tables, along with answers to common questions.

Definitions of Ohm and Milliohm

Let’s get started by understanding the key definitions of Ohm (Ω) and Milliohm (mΩ). Understanding these terms will allow you to perform conversions confidently.

What is Ohm?

The ohm (Ω) is the SI derived unit of electrical resistance. It is defined as the resistance between two points of a conductor when a constant potential difference of one volt is applied across those points, producing a current of one ampere in the conductor, assuming no additional electromotive force is present.[1]

What is Ohm? The definition and illustration
What is Ohm (Ω)?

According to SI prefixes[2], which are based on powers of 10, an ohm (1 Ω) is equivalent to one thousand milliohms (103 or 1,000 mΩ).

Ohms to Milliohms conversion scale
Ohms to milliohms conversion scale

What is Milliohm?

A milliohm (mΩ) is a unit of electrical resistance in the SI system equal to one thousandth (1/1,000) of an ohm (10-3 Ω).

What is Milliohm (mΩ)?
What is Milliohm (mΩ)?

It is commonly used in fields such as power distribution, precision electronic testing, and industrial motor evaluation. Accurately measuring very low resistance values is essential for determining the efficiency and reliability of these systems.

Ω to mΩ formula

Let’s take a closer look at the conversion formula so you can carry out these conversions independently, whether using a calculator or doing it manually with pencil and paper.

SI Prefixes and Values
SI multiples and submultiples

The milli- prefix in the International System of Units (SI) represents a multiplier of 10-3 (0.001). So, to convert from ohms to milliohms, multiply the number of ohms (R(Ω)) by 103 (1,000).

R(mΩ) = R(Ω) × 103 = R(Ω) × 1,000

$$\text{R}_\text{(mΩ)} = \text{R}_\text{(Ω)} \times 1{,}000$$

Or remember the Ω-to-mΩ conversion factor: 1 Ω = 1,000 mΩ

Ω to mΩ conversion table

The conversion table below provides a handy reference for converting electrical resistance measurement units from ohms (Ω) to milliohms (mΩ). It covers a range from 0.1 Ω to 1,000 Ω, allowing for easy and quick conversions between these units of measurement.

Ohms (Ω)Milliohms (mΩ)
0.1 Ω100 mΩ
0.5 Ω500 mΩ
1 Ω1,000 mΩ
2 Ω2,000 mΩ
4 Ω4,000 mΩ
5 Ω5,000 mΩ
10 Ω10,000 mΩ
20 Ω20,000 mΩ
30 Ω30,000 mΩ
40 Ω40,000 mΩ
50 Ω50,000 mΩ
60 Ω60,000 mΩ
70 Ω70,000 mΩ
80 Ω80,000 mΩ
90 Ω90,000 mΩ
100 Ω100,000 mΩ
200 Ω200,000 mΩ
500 Ω500,000 mΩ
800 Ω800,000 mΩ
1,000 Ω1,000,000 mΩ
Ohms to milliohms (Ω to mΩ) conversion table

Examples

Now, let's look at an example that illustrates the calculations required to convert from ohms to milliohms (Ω to mΩ).

Example: Shunt Resistor Calibration in Power Systems

Shunt resistors used for current measurement in power circuits often have milliohm-level resistances for accurate voltage drop assessments.

If a shunt resistor is rated at 0.0009 Ω, what is its value in milliohms? You need it for precise current monitoring.

Solution

Since 1 ohm (Ω) = 103 = 1,000 milliohms (mΩ), we can convert 0.0009 Ω to milliohms by using the following formula:

$$\text{R}_\text{(mΩ)} = \text{R}_\text{(Ω)} \times 1{,}000$$
$$\text{R}_\text{(mΩ)} = 0.0009 \times 1{,}000 = \boxed{0.9 \text{ mΩ}}$$

Therefore, the 0.0009 Ω electrical resistance is equivalent to 0.9 mΩ.

To solve the problem with our calculator, follow the steps below:

  1. Enter the value in ohms: For this example, enter 0.0009 into the From box.
  2. View the result: The converter instantly calculates and displays the equivalent value in milliohms: 0.9 mΩ.
Ohms to Milliohms Converter Example
Steps to convert from ohms to milliohms with our calculator

FAQs

Is 1 ohm or 1 milliohm larger?

An ohm (Ω) is a thousand times bigger than a milliohm (mΩ). Here are the relationships between the units:

  • 1 Ω = 103 = 1,000 mΩ
  • 1 mΩ = 10-3 = 1 ÷ 1,000 = 0.001 Ω

How to convert from ohms to milliohms?

To convert electrical resistance from ohms (Ω) to milliohms (mΩ), follow these simple steps:

  • Write down the electrical resistance value in ohms (Ω).
  • Multiply it by the value of a Ω-to-mΩ conversion factor: 103 or 1,000.
  • The result of multiplication is the value of the electrical resistance in milliohms (mΩ).

Why do I need to convert ohms to milliohms?

You convert ohms to milliohms (mΩ) to measure critical small resistances that impact real-world systems. Whole ohms are too imprecise to detect issues like loose connections in EV batteries or corrosion in power cables.

Even 0.005Ω (5mΩ) of extra resistance can cause overheating, energy waste, or equipment failure in high-current circuits. Using milliohms aligns with diagnostic tools and engineering specs, helping you identify hidden risks early.

You now know how to convert electrical resistance from ohms (Ω) to milliohms (mΩ). You can quickly use our calculator to convert between the electric resistance measurement units to save time for future calculations.

Ohm (Ω) to Milliohm (mΩ) Converter

About this app

Ohm (Ω) to Milliohm (mΩ) Converter

Our ohms to milliohms (Ω to mΩ) converter is a simple web app for converting electrical resistance measurement units between ohms (Ω) and milliohms (mΩ), with explanations, formulas, examples, and tables.

Availability

You can use the calculator for free as a PWA web app online or install it locally on any modern operating system, including Android, iOS, Windows 11/10, and macOS.

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References

2 Sources

  1. ⬆️ Wikipedia contributors. (2025, May 25). Ohm.

    https://en.wikipedia.org/w/index.php?title=Ohm&oldid=1292104943
  2. ⬆️ Metric (SI) Prefixes | NIST. (2010, January 13). NIST.

    https://www.nist.gov/pml/owm/metric-si-prefixes