Accurate conversion of resistance units is crucial for engineers, electricians, and students. Manually converting between units like milliohms, ohms, and megaohms is time-consuming and error-prone, which can lead to costly mistakes in circuit design, repairs, or experiments.
Our electrical resistance unit converter simplifies this task by quickly and accurately converting values across various units, from attoohms (aΩ) to exaohms (EΩ). Simply input your value, select the units, and receive reliable results instantly.
Let's begin by reviewing the essential definitions that equip you with the understanding needed to perform conversions with precision and reliability.
Definitions
What is Electrical Resistance?
Electrical resistance is a measure of a material’s opposition to the flow of electric current. It quantifies the difficulty that electrons experience when moving through a conductor, much like friction opposes motion in mechanical systems.[1]
This opposition is quantified by Ohm’s law as the ratio of the voltage (V) to the current (I), expressed as R = V/I.
Additionally, resistance depends on the material’s intrinsic resistivity (ρ) and its physical dimensions, as shown in the formula R = ρL/A, where L is the length and A is the cross-sectional area. Resistance is measured in ohms (Ω).[2]
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.[3]
In short, the electrical resistance is the property of a material that opposes electric current flow. The ohm (Ω) is the SI unit used to measure that resistance.
SI Units
The SI (International System of Units) unit system[4] follows a decimal-based structure, where each unit is a multiple or fraction of 10 (10⁰, 10¹, 10², etc.). The table below lists the standard SI prefixes for ohms, along with their symbols, multipliers, and names.
| Submultiples | Multiples | ||||
|---|---|---|---|---|---|
| Value | SI symbol | Name | Value | SI symbol | Name |
| 10−1 Ω | dΩ | deciohm | 101 Ω | daΩ | decaohm |
| 10−2 Ω | cΩ | centiohm | 102 Ω | hΩ | hectoohm |
| 10−3 Ω | mΩ | milliohm | 103 Ω | kΩ | kiloohm |
| 10−6 Ω | μΩ | microohm | 106 Ω | MΩ | megaohm |
| 10−9 Ω | nΩ | nanoohm | 109 Ω | GΩ | gigaohm |
| 10−12 Ω | pΩ | picoohm | 1012 Ω | TΩ | teraohm |
| 10−15 Ω | fΩ | femtoohm | 1015 Ω | PΩ | petaohm |
| 10−18 Ω | aΩ | attoohm | 1018 Ω | EΩ | exaohm |
| 10−21 Ω | zΩ | zeptoohm | 1021 Ω | ZΩ | zettaohm |
| 10−24 Ω | yΩ | yoctoohm | 1024 Ω | YΩ | yottaohm |
| 10−27 Ω | rΩ | rontoohm | 1027 Ω | RΩ | ronnaohm |
| 10−30 Ω | qΩ | quectoohm | 1030 Ω | QΩ | quettaohm |
These prefixes help simplify electrical resistance measurements across a wide range of applications, from microelectronics to high-power systems.
Conversion table
The table below provides a quick reference for converting commonly used ohm units, ranging from nanoohms to gigaohms, to help you perform conversions efficiently.
| From | Nanoohm | Microohm | Milliohm | Ohm | Kiloohm | Megaohm | Gigaohm |
|---|---|---|---|---|---|---|---|
| 1 nanoohm = | 1 nΩ | 0.001 µΩ | 0.000001 mΩ | 0.000000001 Ω | 0.000000000001 kΩ | 0.000000000000001 MΩ | 0.000000000000000001 GΩ |
| 1 microohm = | 1,000 nΩ | 1 µΩ | 0.001 mΩ | 0.000001 Ω | 0.000000001 kΩ | 0.000000000001 MΩ | 0.000000000000001 GΩ |
| 1 milliohm = | 1,000,000 nΩ | 1,000 µΩ | 1 mΩ | 0.001 Ω | 0.000001 kΩ | 0.000000001 MΩ | 0.000000000001 GΩ |
| 1 ohm = | 1,000,000,000 nΩ | 1,000,000 µΩ | 1,000 mΩ | 1 Ω | 0.001 kΩ | 0.000001 MΩ | 0.000000001 GΩ |
| 1 kiloohm = | 1,000,000,000,000 nΩ | 1,000,000,000 µΩ | 1,000,000 mΩ | 1,000 Ω | 1 kΩ | 0.001 MΩ | 0.000001 GΩ |
| 1 megaohm = | 1,000,000,000,000,000 nΩ | 1,000,000,000,000 µΩ | 1,000,000,000 mΩ | 1,000,000 Ω | 1,000 kΩ | 1 MΩ | 0.001 GΩ |
| 1 gigaohm = | 1,000,000,000,000,000,000 nΩ | 1,000,000,000,000,000 µΩ | 1,000,000,000,000 mΩ | 1,000,000,000 Ω | 1,000,000 kΩ | 1,000 MΩ | 1 GΩ |
Examples
The following examples demonstrate how to convert between different electrical resistance units, helping you apply these calculations in practical scenarios.
Example 1: High-Precision Resistor Testing
Electronics engineers measure extremely low resistance values in precision resistors. Converting microohms to ohms ensures accurate component selection and quality control.
If a resistor has a measured resistance of 250 μΩ, what is the resistance in ohms? You need it to verify circuit specifications.
Solution
Since 1 ohm (Ω) = 106 = 1,000,000 microohms (µΩ), we can convert 250 µΩ to Ω using the following formula:
Therefore, 250 µΩ electrical resistance is equivalent to 0.00025 Ω.
To solve the problem with our calculator, follow the steps below:
- Select the "From" unit: Choose
µΩ = Microohmfrom the dropdown menu. - Select the "To" unit: Choose
Ω = Ohmfrom the dropdown menu. - Enter the value in microohms: For this example, enter
250into theFrombox. - View the result: The converter instantly calculates and displays the equivalent value in ohms:
0.00025 Ω.
Example 2: Automotive Sensor Resistance Measurement
Vehicle sensors, such as oxygen sensors, operate with low resistance values, requiring conversions for diagnostics and calibration.
If an oxygen sensor has a resistance of 0.5 Ω, what is its resistance in milliohms? You need it to check sensor accuracy.
Solution
Since 1 ohm (Ω) = 1,000 milliohms (mΩ), we can convert 0.5 Ω to mΩ using the following formula:
Therefore, 0.5 Ω electrical resistance is equivalent to 500 mΩ.
To solve the problem with our calculator, follow the steps below:
- Select the "From" unit: Choose
Ω = Ohmfrom the dropdown menu. - Select the "To" unit: Choose
mΩ = Milliohmfrom the dropdown menu. - Enter the value in ohms: For this example, enter
0.5into theFrombox. - View the result: The converter instantly calculates and displays the equivalent value in milliohms:
500 mΩ.
You now know how to convert between electrical resistance units. You can quickly use our calculator to convert between the measurement units to save time for future calculations.
