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]
According to SI prefixes[2], which are based on powers of 10, an ohm (1 Ω) is equivalent to one thousand milliohms (103 mΩ or 1,000 mΩ).
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).
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.
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
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 Ω | 100 mΩ |
| 0.5 Ω | 500 mΩ |
| 1 Ω | 1,000 mΩ |
| 2 Ω | 2,000 mΩ |
| 4 Ω | 4,000 mΩ |
| 5 Ω | 5,000 mΩ |
| 10 Ω | 10,000 mΩ |
| 20 Ω | 20,000 mΩ |
| 30 Ω | 30,000 mΩ |
| 40 Ω | 40,000 mΩ |
| 50 Ω | 50,000 mΩ |
| 60 Ω | 60,000 mΩ |
| 70 Ω | 70,000 mΩ |
| 80 Ω | 80,000 mΩ |
| 90 Ω | 90,000 mΩ |
| 100 Ω | 100,000 mΩ |
| 200 Ω | 200,000 mΩ |
| 500 Ω | 500,000 mΩ |
| 800 Ω | 800,000 mΩ |
| 1,000 Ω | 1,000,000 mΩ |
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:
Therefore, the 0.0009 Ω electrical resistance is equivalent to 0.9 mΩ.
To solve the problem with our calculator, follow the steps below:
- Enter the value in ohms: For this example, enter
0.0009into the From box. - View the result: The converter instantly calculates and displays the equivalent value in milliohms:
0.9 mΩ.
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 mΩ1 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-mΩconversion factor:103or1,000. - 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.
