Magnetic Field Strength Converter
ScienceConvert magnetic field strength (H field) between amperes per metre and oersted instantly — distinct from magnetic flux density (Tesla/Gauss).
From
To
All conversionsfor 1 Oersted (Oe)
| Kiloamperes per Metre (kA/m) | 0.0795775 |
| Amperes per Metre (A/m) | 79.5775 |
| Oersted (Oe) | 1 |
What is a Magnetic Field Strength?
The Magnetic Field Strength Converter converts magnetic field strength (the H field) between amperes per metre, kiloamperes per metre (SI), and oersted (the legacy CGS unit). Magnetic field strength measures the magnetizing force applied to create a magnetic field — distinct from magnetic flux density (the B field), which the existing Magnetic Field Converter covers, and which measures the resulting field within a material.
Enter a value in any supported unit and the converter calculates the equivalent instantly. For the related driving-force quantity, see the Magnetomotive Force Converter.
How to use this Magnetic Field Strength calculator
- Choose your starting unit from the source dropdown — for example, "Oersted (Oe)".
- Enter the numeric value you want to convert in the input field.
- Choose your target unit from the destination dropdown — for example, "Amperes per Metre (A/m)".
- Read the converted result, which updates instantly as you type or change units.
- Use the swap (⇅) button if you need to reverse the conversion direction.
- Use the copy button to grab the result for a magnet specification comparison or electromagnet design calculation.
Formula & Methodology
The converter's base unit is amperes per metre (A/m). Every supported unit has a fixed multiplier: - 1 kiloampere per metre (kA/m) = 1,000 A/m - 1 oersted (Oe) ≈ 79.5775 A/m Any conversion follows: Result = Input × (toBase of source unit ÷ toBase of target unit) Worked example — converting a permanent magnet's coercivity of 12,000 Oe to kA/m: Result = 12,000 × (79.5775 ÷ 1,000) = 954.93 kA/m This is the SI-unit equivalent you'd use in a modern engineering calculation involving that magnet's coercivity.
Frequently Asked Questions
Magnetic field strength (the H field, in amperes per metre) measures the magnetizing force applied to create a magnetic field, while magnetic flux density (the B field, in Tesla or Gauss, covered by the existing [Magnetic Field Converter](/magnetic-field-converter/)) measures the resulting magnetic field within a material. The two are related by the material's magnetic permeability, and are equal in a vacuum but can differ significantly inside magnetic materials.
Multiply the oersted value by 79.5775, since one oersted equals approximately 79.5775 amperes per metre. Enter your value with 'Oersted (Oe)' as the source and 'Amperes per Metre (A/m)' as the target to apply this automatically.
Oersted (the CGS unit) remains the conventional unit for specifying coercivity and other magnetic material properties in many industries, particularly for permanent magnets and magnetic recording media, due to long-standing convention even though SI units are the modern scientific standard.
Magnetic field strength equals magnetomotive force divided by the length of the magnetic path (H = MMF/length) — field strength is MMF distributed along a specific path, while MMF is the total driving force. See the [Magnetomotive Force Converter](/magnetomotive-force-converter/) for that related quantity.
Coercivity is the magnetic field strength required to reduce a magnetized material's magnetization to zero, commonly specified in oersted for permanent magnet materials — a higher coercivity indicates a magnet more resistant to demagnetization.
This depends entirely on the solenoid's winding density (turns per unit length) and current — a solenoid with 1,000 turns per metre carrying 1 amp produces a field strength of 1,000 A/m, and the value scales directly with both factors.
In a vacuum (or air, approximately), magnetic flux density (B) equals magnetic field strength (H) multiplied by the permeability of free space — a fixed constant — making the two values proportional in non-magnetic environments, though they diverge significantly inside ferromagnetic materials.
Ferromagnetic materials respond non-linearly to an applied field, so datasheets typically show a full B-H curve (hysteresis loop) rather than a single conversion factor, since the relationship between applied field strength and resulting flux density depends on the material's magnetic history and saturation behaviour.
Permanent magnet manufacturing, magnetic recording media design, electromagnet and solenoid engineering, and materials science research into magnetic properties all routinely work with magnetic field strength data, often needing conversion between the SI A/m and legacy CGS oersted units.
No — magnetic field strength can vary at different points within a magnetic circuit, particularly at boundaries between materials with different permeabilities, which is why magnetic circuit analysis often requires calculating field strength separately for each segment of the path.
Also known as