Magnetic Field Strength (H

Magnetic Field Strength (H), Oersteds & Flux Density (B) Metrology

Magnetic Field Strength (H, also called magnetic field intensity or magnetizing force) quantifies the magnetic excitation generated by electric currents, independent of the medium's magnetic response:

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• Universal Field Intensity Conversion Formulas (SI & CGS)**:

1 Oersted (Oe) = (1,000) / (4π) A/m ≈ 79.57747 A/m = 0.079577 kA/m = 0.79577 A/cm

1 Ampere/meter = (4π) / (1,000) Oe ≈ 0.01256637 Oe = 12.56637 mOe = 10^-3 kA/m

1 A/cm = 100 A/m = 1.256637 Oe | 1 A/in = 39.370 A/m = 0.4947 Oe

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• The Fundamental Relationship Between H and B**:

B = μ H = μ_r μ_0 H = μ_0

Where μ_0 = 4π × 10^-7 H/m ≈ 1.256637 × 10^-6 T/

In vacuum/air: 1 Oe 1 Gauss = 10^-4 Tesla = 100\ μT

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• Standard Electromagnetic Field Benchmarks**:

• Earth Surface Geomagnetic Field: 39.79 A/m = 0.50 Oe B = 50.0\ μT = 0.50 Gauss

• Industrial Solenoid Coil: 1,000.0 A/m = 12.57 Oe B_0 = 1.257 mT = 12.57 Gauss

• Silicon Steel Core: 200.0 A/m = 2.51 Oe μ_r = 4000 B = 1.005 Tesla = 10,053 G

• NdFeB N52 Coercivity: 875.0 kA/m = 10,996 Oe Intrinsic demagnetization threshold H_cj

• 3.0T MRI Superconducting Magnet: 2,387.3 kA/m = 30,000 Oe B_0 = 3.00 Tesla

How to Use This Calculator

Enter your Magnetic Field Strength (H / Magnetizing Force) (e.g. 1000 in H), From Magnetic Field Strength Unit — choose from Amperes per meter (A/m = At/m - SI Base Standard), Oersteds (Oe = (1000/4π) A/m ≈ 79.577 A/m - CGS Unit), Kiloamperes per meter (kA/m = 1,000 A/m), To Magnetic Field Strength Unit — choose from Oersteds (Oe), Amperes per meter (A/m), Kiloamperes per meter (kA/m), Medium Relative Permeability (μ_r) (e.g. 1.0 for air, 2000 for ferrite in μ_r), and Electromagnetic Field Benchmark — choose from Custom Field Strength, Earth Geomagnetic Surface Field (39.79 A/m = 0.50 Oe) → B = 50.0 µT (0.50 Gauss), Industrial Solenoid Coil (1,000.0 A/m = 12.57 Oe) → B₀ = 1.257 mT (12.57 Gauss in air). Results update instantly as you type — adjust any value to compare scenarios.

The Formula

Magnetic Flux Density B = mu_r mu_0 H (Tesla)

Worked Example

A magnetics engineer evaluating the coercivity of an NdFeB permanent magnet rated at 11,000 Oersteds multiplies by 79.5775 to find the coercivity is 875.35 kA/m, ensuring the magnet will not demagnetize under opposing stator field surges.

Understanding Your Result

Unit conversions are exact by definition within a given measurement system (e.g., 1 km = exactly 1,000 m). Cross-system conversions (metric to imperial) use defined exchange factors: 1 inch = exactly 2.54 cm; 1 pound = 0.45359237 kg. Round your converted result to match the precision of your original measurement — expressing more decimal places than your input justifies implies false accuracy. For regulatory, legal, or safety-critical applications, verify which measurement system is required by the applicable standard.