Magnetic Field Converter
ScienceConvert magnetic flux density units instantly — tesla, millitesla, microtesla, nanotesla, gauss, and kilogauss. Used in MRI, geophysics, and electronics.
From
To
All conversionsfor 1 Gauss (G)
| Tesla (T) | 0.0001 |
| Millitesla (mT) | 0.1 |
| Microtesla (µT) | 100 |
| Nanotesla (nT) | 100000 |
| Picotesla (pT) | 100000000 |
| Gauss (G) | 1 |
| Milligauss (mG) | 1000 |
| Kilogauss (kG) | 0.001 |
| Weber/metre² (Wb/m²) | 0.0001 |
What is a Magnetic Field?
A Magnetic Field Converter translates between the units of magnetic flux density — the quantity that describes the strength of a magnetic field at a point in space. The SI unit is the tesla (T), and the CGS unit is the gauss (G). Both are in common use: tesla dominates in physics, engineering, and medicine; gauss remains prevalent in materials science, geophysics, and everyday descriptions of permanent magnet strength.
The converter covers 9 units across the SI and CGS systems, from picotsela (pT, 10⁻¹² T) for ultra-sensitive magnetometry to kilogauss (kG, 0.1 T) for characterising permanent magnets.
Key reference points:
- Earth's field: ~50 µT = ~0.5 G
- Fridge magnet: ~5 mT = ~50 G
- NdFeB permanent magnet (surface): ~0.5–1.4 T = ~5,000–14,000 G
- Clinical MRI: 1.5–3 T = 15,000–30,000 G
- Proton NMR (600 MHz): ~14 T
For electric field strength and related electrical quantities, see the Capacitance Converter and Electric Resistance Converter.
How to use this Magnetic Field calculator
- Enter the magnetic field value in the From field.
- Select the From unit (e.g. Gauss).
- Select the To unit (e.g. Tesla).
- The converted value appears instantly.
- The reference table shows all units simultaneously.
- Click ⇄ to reverse the conversion direction.
Formula & Methodology
Base unit: Tesla (T) | Unit | Tesla equivalent | |---|---| | T | 1 | | mT | 0.001 | | µT | 10⁻⁶ | | nT | 10⁻⁹ | | pT | 10⁻¹² | | G (gauss) | 0.0001 | | mG | 10⁻⁷ | | kG | 0.1 | | Wb/m² | 1 (identical to T) | Worked example: Convert 12,000 G (typical NdFeB magnet) to tesla. - 12,000 × 0.0001 = 1.2 T Reference fields: | Source | Approx. B | |---|---| | Earth's surface (India) | 35–45 µT | | Fridge magnet | 5–10 mT | | Loudspeaker magnet | 1–2.5 T | | Clinical MRI | 1.5–3 T | | NdFeB N52 magnet | ~1.4 T at surface |
Frequently Asked Questions
What is magnetic flux density?
Magnetic flux density (symbol B) measures the strength of a magnetic field passing through a unit area perpendicular to the field. It quantifies how concentrated the magnetic field lines are. The SI unit is the tesla (T), and it is the quantity measured by a gaussmeter or Hall-effect sensor. It is sometimes loosely called 'magnetic field strength', though that term technically refers to H (measured in A/m).
What is the relationship between tesla and gauss?
1 tesla = 10,000 gauss. The tesla is the SI unit, defined as 1 Wb/m² (weber per square metre). The gauss is the CGS unit. Both are commonly used: tesla for strong fields (MRI machines, NdFeB magnets), gauss for weak fields (Earth's magnetic field, which is approximately 0.25–0.65 gauss = 25–65 microtesla).
What is Earth's magnetic field in tesla?
Earth's surface magnetic field varies from about 25 µT (microtesla) near the equator to about 65 µT near the poles. This is approximately 0.25–0.65 gauss. The field is not uniform — it varies with location, altitude, and solar activity. India's surface field is approximately 35–45 µT.
What magnetic field strength does an MRI machine produce?
Clinical MRI machines typically use magnetic fields of 1.5 T or 3 T (tesla). Research MRI systems can reach 7 T or higher. These fields are extremely strong — 15,000 to 70,000 times the strength of Earth's magnetic field — which is why ferromagnetic objects must be kept away from MRI rooms.
What are nanotesla (nT) used for?
Nanotesla (nT) are used in geophysics and magnetometry for measuring very weak magnetic fields. Earth's field in nT is approximately 25,000–65,000 nT (= 25–65 µT). Anomalies in Earth's field due to geological features are measured in nT, and magnetometers on satellites and aircraft survey these variations to find mineral deposits and tectonic structures.
What magnets produce the highest commercially available flux density?
Neodymium iron boron (NdFeB) permanent magnets are the strongest commercially available, with surface flux densities of 0.5–1.4 T depending on grade. The strongest NdFeB grade (N52) achieves approximately 1.4–1.5 T at the surface. Electromagnets and superconducting magnets can reach much higher fields in laboratory settings.
What is a Weber/metre² (Wb/m²)?
Weber per square metre (Wb/m²) is the definition of the tesla. 1 T = 1 Wb/m². The weber (Wb) is the SI unit of magnetic flux, equal to one volt-second. The tesla is named after Nikola Tesla and the weber after Wilhelm Eduard Weber. They are the same quantity expressed differently — the converter includes both for completeness.
What safety limits apply to magnetic field exposure?
ICNIRP (International Commission on Non-Ionizing Radiation Protection) guidelines limit occupational exposure to static magnetic fields to 2 T for the head and trunk and 8 T for the extremities. For the general public, the reference level is 400 mT. MRI workers are routinely exposed up to 0.5 T and are subject to periodic health monitoring.
How are magnetic fields used in electronics manufacturing?
Magnetic field converters are used in electronics when specifying Hall-effect sensors, inductors, transformers, and shielding materials. Sensor datasheets may give sensitivity in mT or gauss; transformer core saturation is specified in mT or T; and EMC shielding effectiveness is evaluated at specific field strengths in µT.
What is the difference between magnetic field strength (H) and magnetic flux density (B)?
Magnetic field strength H (measured in A/m or Oersted) is the excitation field produced by free currents. Magnetic flux density B (measured in T or gauss) is the total field including the contribution of the material's magnetisation. In vacuum/air, B = µ₀H (where µ₀ = 4π × 10⁻⁷ H/m). Inside a magnetic material, B = µ₀µᵣH where µᵣ is the relative permeability. This converter handles B (flux density) only.