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Magnetic Field Converter

Converter

Convert Magnetic Field

From Unit:

To Unit:

Result

Enter a value and select units to see the result.

About This Tool

Magnetic Field Converter – Tesla, Gauss, Oersted and More

Magnetic fields are described by two distinct but related quantities: magnetic flux density (B) and magnetic field intensity (H). This converter handles all major units for both groups — from Tesla and Gauss used by physicists and MRI engineers, to Nanotesla used in geophysics, to Oersted and Ampere per meter used in electromagnetics. Enter a value, choose your units, and the result — plus an all-units reference table — appears instantly.

B-Field vs H-Field: Why Two Systems?

The B-field (magnetic flux density) is what you measure with a Hall-effect sensor or a gaussmeter. It includes contributions from both free currents and the magnetisation of any material present. Its SI unit is the Tesla (T), and its CGS counterpart is the Gauss (G) — where 1 T = 10,000 G.

The H-field (magnetic field intensity) represents only the contribution of free currents, independent of the medium. Its SI unit is Ampere per meter (A/m), and its CGS equivalent is the Oersted (Oe) — where 1 Oe ≈ 79.58 A/m.

B and H are related through the equation B = µH, where µ is the magnetic permeability of the medium. In free space, µ₀ = 4π × 10⁻⁷ T·m/A. Inside ferromagnetic materials, µ can be thousands of times higher. Because µ varies by material, this tool does not convert between B-field and H-field units — doing so would silently give a wrong answer. Instead, it shows a clear explanation if you attempt such a conversion.

Supported Units

B-field (flux density) units: Tesla (T), Millitesla (mT), Microtesla (µT), Nanotesla (nT), Gauss (G), Milligauss (mG), Weber per square meter (Wb/m²), Maxwell per square centimeter (Mx/cm²), and Gamma (γ). All conversions in this group normalise through Tesla as the base unit.

H-field (intensity) units: Ampere per meter (A/m), Kiloampere per meter (kA/m), and Oersted (Oe). Conversions normalise through A/m.

Conversion Factors at a Glance

Key B-field relationships anchored to 1 Tesla:

  • 1 T = 1,000 mT = 1,000,000 µT = 1,000,000,000 nT
  • 1 T = 10,000 G = 10,000,000 mG
  • 1 T = 1 Wb/m² = 10,000 Mx/cm²
  • 1 T = 1,000,000,000 γ (gamma)

Key H-field relationships anchored to 1 Oersted:

  • 1 Oe = 1,000 / (4π) A/m ≈ 79.5775 A/m
  • 1 kA/m = 1,000 A/m ≈ 12.566 Oe

Real-World Magnetic Field Reference

Understanding where your value falls on the real-world scale helps put conversions in context:

  • Earth's magnetic field: approximately 25–65 µT (25,000–65,000 nT), depending on location.
  • Refrigerator magnet: roughly 1–10 mT on the surface.
  • Neodymium (NdFeB) magnet: surface field around 0.5–1.5 T.
  • Clinical MRI scanner: 1.5 T (1,500 mT) or 3 T (30,000 G) field strength.
  • Research electromagnets: 10–20 T, and pulse magnets can exceed 45 T.
  • Neutron star surface: 10⁸ T or more — extraordinary fields in astrophysics.

Who Uses This Converter?

Physicists and electrical engineers routinely need to move between SI and CGS unit systems when reading legacy literature or comparing results across labs. MRI technicians work in Tesla and Millitesla for field-strength specifications, while geophysicists report survey results in Nanotesla or Gamma. EMC specialists measure interference fields in Microtesla and Milligauss. Materials scientists specify hard-magnetic coercivity in Oersted or kA/m. This tool covers all these communities in a single interface.

Precision and Scientific Notation

Magnetic field values span an enormous dynamic range — from the sub-nanotesla fields detected by SQUID magnetometers to the megatesla fields of neutron stars. The converter handles this by automatically switching to scientific notation for values smaller than 10⁻⁶ or larger than 10¹². The precision slider (0–10 decimal places) gives you control over how many digits are shown in the output without affecting the underlying calculation accuracy.

Using the All-Units Table

The output panel shows an all-units reference table listing your input value converted into every supported unit in the same group simultaneously. This is useful when you need to quote a value across multiple standards in a report, or when you want to cross-check a number against an unfamiliar unit. The row corresponding to your selected output unit is highlighted for quick reading. You can copy the entire table to the clipboard with the Copy Result button.

Frequently Asked Questions

Is the Magnetic Field Converter free?

Yes, Magnetic Field Converter is totally free :)

Can I use the Magnetic Field Converter offline?

Yes, you can install the webapp as PWA.

Is it safe to use Magnetic Field Converter?

Yes, any data related to Magnetic Field Converter only stored in your browser (if storage required). You can simply clear browser cache to clear all the stored data. We do not store any data on server.

How does this magnetic field converter work?

The converter normalises your input to the base unit of its group — Tesla for B-field (flux density) units or Ampere per meter for H-field (intensity) units — and then multiplies by the target unit's conversion factor. All arithmetic uses exact rational factors, so the only source of rounding is the precision setting you choose.

What is the difference between B-field and H-field?

B is the magnetic flux density (in Tesla or Gauss) — the total field experienced at a point in space, including the effect of any nearby material. H is the magnetic field intensity (in A/m or Oersted) — the field produced by free currents alone, independent of the medium. They are related by B = µH, where µ is the permeability of the medium.

Why can't I convert between Tesla and Oersted directly?

Tesla (B-field) and Oersted (H-field) measure different physical quantities. Converting between them requires knowing the magnetic permeability of the material (µ). In free space µ₀ ≈ 4π × 10⁻⁷ T·m/A, but inside materials it varies widely. This tool intentionally blocks cross-group conversions and shows a clear explanation when you try.

What units does this tool support?

B-field units: Tesla (T), Millitesla (mT), Microtesla (µT), Nanotesla (nT), Gauss (G), Milligauss (mG), Weber per square meter (Wb/m²), Maxwell per square centimeter (Mx/cm²), and Gamma (γ). H-field units: Ampere per meter (A/m), Kiloampere per meter (kA/m), and Oersted (Oe).

What are typical real-world magnetic field strengths?

The Earth's magnetic field is roughly 25–65 µT. A refrigerator magnet produces about 5 mT. Clinical MRI scanners operate at 1.5 T to 3 T. Strong research magnets reach 20–45 T. Neutron star surface fields can exceed 10⁸ T. The all-units table in the tool lets you see your value in context across the full range of supported units.

Can this converter handle very small or very large values?

Yes. The tool accepts any finite number, including scientific notation input (e.g., 1.5e-6), and automatically switches to scientific notation output for values smaller than 10⁻⁶ or larger than 10¹². The precision slider lets you control decimal places from 0 to 10.