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Magnetic Field Strength Converter
Tool Description
Magnetic Field Strength Converter is an online magnetic field strength unit converter that supports mutual conversion between ampere/meter (A/m), ampere/centimeter (A/cm), kiloampere/meter (kA/m), oersted (Oe), and kilo-oersted (kOe). Simply enter any value and unit to instantly see the corresponding results in all other units. Suitable for electromagnetism calculations, magnetic material research, motor design, physics education, and more.
How to Use
- Enter a value
Input the value to convert in the input box, supporting integers and decimals such as
100,0.5 - Select source unit
Choose the magnetic field strength unit of the current value from the dropdown list (A/m/A/cm/kA/m/Oe/kOe)
- View results
Click the "Convert" button or press Enter. The results area below will display corresponding values in all units, with a copy button on the right of each result for convenient use
Use Cases
- Magnetic Material Research: The coercivity (Hc) of permanent magnet materials is often expressed in oersted (Oe) or kilo-oersted (kOe), while international standards use ampere/meter (A/m) or kiloampere/meter (kA/m). Use this tool to quickly convert between different unit systems and compare literature and product parameters from different countries
- Motor and Transformer Design: Magnetic field strength in motor magnetic circuits and transformer cores is a key design parameter. Western literature often uses oersted (Oe), while Chinese design specifications use ampere/meter (A/m). Use this tool during the design phase to unify units and avoid conversion errors
- Physics and Electromagnetism Education: In electromagnetism courses, magnetic field strength H is one of the fundamental physical quantities. Students can use this tool to intuitively understand the conversion relationship between the SI system (A/m) and the CGS system (Oe), deepening their understanding of electromagnetic concepts
Key Advantages
- Free and Easy
The tool is completely free, requiring no registration or installation. Just open the page and start using it, lowering the barrier to entry.
- Local Computation
All conversions run in your browser; your input data is never uploaded to a server, ensuring privacy and security.
- Instant to Use
The interface is clean and intuitive. Enter a value and unit to get all results with one click—no complex operations to learn.
- Full Coverage
Supports mutual conversion among major magnetic field strength units such as ampere/meter, ampere/centimeter, kiloampere/meter, oersted, and kilo-oersted.
- Accurate Results
Uses a high-precision conversion factor—oersted to 1 Oe = 1000/(4π) ≈ 79.5775 A/m—delivering stable and reliable results.
- One-Click Copy
Each result has a copy button on the right, so you can quickly paste values into documents or spreadsheets for further use.
Magnetic Field Strength Unit Conversion Relationships
The following shows the conversion relationships between magnetic field strength units, with ampere/meter (A/m) as the base unit:
| Unit Name | Abbreviation | Conversion Relationship | Equivalent A/m |
|---|---|---|---|
| Ampere/Meter | A/m | 1 A/m (SI standard unit) | 1 |
| Ampere/Centimeter | A/cm | 1 A/cm = 100 A/m | 100 |
| Kiloampere/Meter | kA/m | 1 kA/m = 1,000 A/m | 1,000 |
| Oersted | Oe | 1 Oe = 1000/(4π) A/m | 79.5774715459 |
| Kilo-oersted | kOe | 1 kOe = 1,000 Oe | 79,577.4715459 |
Common Magnetic Field Strength Reference Values
The following shows typical magnetic field strength ranges in different application scenarios for reference and comparison:
| Scenario/Object | Magnetic Field Strength |
|---|---|
| Geomagnetic field (equator) | ~40 A/m |
| Geomagnetic field (poles) | ~80 A/m |
| Surface of household appliances | ~160 A/m |
| Surface of small permanent magnets | ~800 A/m |
| Surface of NdFeB permanent magnets | ~4,000 A/m |
| Electromagnet/relay cores | 8,000 ~ 80,000 A/m |
| MRI (Magnetic Resonance Imaging) | 80,000 ~ 800,000 A/m |
| Ultra-strong pulsed magnetic fields | 1,600,000 ~ 2,400,000 A/m |
Difference Between Magnetic Field Strength and Magnetic Flux Density
Magnetic field strength (H) and magnetic flux density (B) are two closely related but conceptually different physical quantities in electromagnetism. Magnetic field strength H describes the magnetic field generated by an external source (such as current or a permanent magnet), with units of ampere/meter (A/m) or oersted (Oe). Magnetic flux density B describes the actual magnetic field in the medium (including the magnetization effect of the medium), with units of tesla (T) or gauss (Gs).
The relationship between the two is: B = μ₀(H + M) = μ₀μᵣH, where μ₀ = 4π×10⁻⁷ H/m is the vacuum permeability, M is the magnetization, and μᵣ is the relative permeability. In vacuum, a magnetic field strength of 1 A/m produces a magnetic flux density of approximately 1.2566×10⁻⁶ T (about 0.012566 Gs). In ferromagnetic materials, due to the large μᵣ (e.g., iron μᵣ≈200~5,000), the same H produces a much larger B.
FAQ
Ampere/meter (A/m) is the standard unit of magnetic field strength H in the International System of Units (SI). It represents the current intensity per unit length. For example, if an infinitely long straight conductor carries a current of 1 ampere, the magnetic field strength at a distance of 1/(2π) meters from the conductor is 1 A/m. Ampere/meter is one of the fundamental units in electromagnetism, widely used in motor design, magnetic material testing, EMC, and other fields.
1 Oe = 1000/(4π) ≈ 79.5775 A/m, 1 A/m = 4π/1000 ≈ 0.012566 Oe. The oersted is the unit of magnetic field strength in the CGS system, named after Danish physicist Hans Christian Ørsted. In the field of magnetic materials, coercivity (Hc) is often labeled in oersted (Oe) or kilo-oersted (kOe). As a rough estimate: 1 Oe ≈ 80 A/m, or 1 kA/m ≈ 12.57 Oe.
Kiloampere/meter (kA/m) is the unit for expressing larger magnetic field strengths in international standards, commonly used for permanent magnet coercivity labeling (e.g., NdFeB Hc≈800~2,000 kA/m), motor air gap magnetic field strength, etc. Kilo-oersted (kOe) is the corresponding unit in the CGS system, commonly found in traditional magnetic material literature (e.g., NdFeB Hc≈10~25 kOe). 1 kOe = 1,000 Oe ≈ 79,577 A/m ≈ 79.58 kA/m.
Magnetic field strength H describes the "magnetic field generated by an external source", measured in A/m or Oe, independent of the medium. Magnetic flux density B (also called magnetic induction) describes the "actual magnetic field in the medium", measured in T or Gs, including the magnetization effect of the medium. The relationship is: B = μ₀μᵣH. In vacuum, μᵣ=1, B = μ₀H ≈ 1.2566×10⁻⁶ H. In magnetic materials, the same H produces a much larger B. Think of it as "H is the cause, B is the effect".
No. All conversion calculations are performed entirely in your browser locally using pure JavaScript math. Your input data never leaves your device, so please feel free to use it.
This tool uses JavaScript double-precision floating-point numbers (64-bit IEEE 754) for calculations, which is sufficiently accurate for most everyday scenarios. The oersted conversion uses the high-precision factor 1 Oe = 1000/(4π) ≈ 79.5774715459 A/m. Up to 6 significant decimal places are retained, with excess digits automatically truncated. For extremely large or small values, minor errors may occur due to floating-point precision limits, but this has virtually no impact in practical applications.
It supports 5 common magnetic field strength units: ampere/meter (A/m), ampere/centimeter (A/cm), kiloampere/meter (kA/m), oersted (Oe), and kilo-oersted (kOe). Enter any unit and value, and the tool immediately shows the corresponding result in the other 4 units, making it easy to switch freely between the SI and CGS systems.
Currently it converts a single value instantly. Enter one value and select the source unit, and the results area shows all target units simultaneously. To process large batches of data, copy the results one by one. For higher-frequency batch needs, member benefits offer a more efficient tool experience.
It wins on being lightweight and instant. Unlike professional electromagnetic simulation software that requires installation and licensing, this tool needs no download and works as soon as you open the page. It covers all everyday magnetic field strength unit conversion needs, ideal for teaching, literature review, and quick checks. For complex electromagnetic field simulation, professional software is still recommended.
It is usually an input format issue. Make sure the input box contains a valid number (integers and decimals such as 100, 0.5) with no spaces, letters, or special symbols. If there is still no result, try refreshing the page and entering again. The tool computes entirely locally, so it is not affected by network fluctuations.
Up to 6 significant decimal places. The tool uses double-precision floating-point calculation and automatically truncates excessively long decimals by default to keep the display readable. If you need higher-precision intermediate values for scientific computing, you can extend them based on the conversion relationship or refer to the tool's published conversion factors.
Yes. The page is responsive and works normally on mobile browsers for input, conversion, and copying. All calculations run locally, so the mobile experience is smooth—no app installation required to convert units anytime, anywhere.
Content last updated：2026-07-17
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