Magnetic Field Converter — Tesla to Gauss Online Free
Converting between magnetic field units is essential for engineers, physicists, medical professionals, and researchers working with electromagnetic systems. Our free Magnetic Field Converter instantly transforms values between Tesla, Gauss, milliTesla, microTesla, nanoTesla, Weber per square meter, and other magnetic flux density units with scientific precision.
What is a Magnetic Field?
A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. It is produced by electric currents, magnetic dipoles, and changing electric fields. The concept of magnetic fields is fundamental to electromagnetism, one of the four fundamental forces of nature.
Magnetic fields are invisible but their effects are observable — from compass needles aligning with Earth's field to the powerful forces in MRI machines. Every magnet, from a tiny refrigerator magnet to a superconducting electromagnet, creates a magnetic field in the surrounding space.
The strength of a magnetic field is quantified by its magnetic flux density (also called magnetic induction), represented by the symbol B. This is what our converter measures and converts between different unit systems.
Magnetic Field Units Explained
Tesla (T) — The SI Unit
The Tesla is the SI unit of magnetic flux density, named after inventor Nikola Tesla. One Tesla is defined as one Weber per square meter, or equivalently, one kilogram per second squared per ampere (kg·s⁻²·A⁻¹). It represents a very strong magnetic field — most everyday magnets produce fields measured in milliTesla or less.
Gauss (G) — The CGS Unit
The Gauss is the centimeter-gram-second (CGS) unit of magnetic flux density, named after mathematician Carl Friedrich Gauss. One Gauss equals 10⁻⁴ Tesla (or 0.0001 T). Despite not being an SI unit, Gauss remains widely used in industry, particularly in the United States, because its magnitude is more convenient for everyday magnetic field measurements.
MilliTesla (mT) and MicroTesla (µT)
MilliTesla (1 mT = 10⁻³ T = 10 G) and microTesla (1 µT = 10⁻⁶ T = 0.01 G) are commonly used SI prefixed units. MilliTesla is convenient for permanent magnets and industrial applications, while microTesla is used for environmental magnetic fields, geophysics, and biomagnetism.
Weber per Square Meter (Wb/m²)
Weber per square meter is dimensionally identical to Tesla (1 Wb/m² = 1 T). The Weber (Wb) is the SI unit of magnetic flux, and dividing by area gives the flux density. This unit explicitly shows the relationship between total flux and the area through which it passes.
Other Units
Additional magnetic field units include the nanoTesla (nT, used in geophysics), Gamma (1 Gamma = 1 nT, an older geophysics unit), Maxwell per square centimeter (equivalent to Gauss), and the Oersted (which measures the H-field rather than B-field). Our converter supports all commonly encountered units.
B-Field vs H-Field: Understanding the Difference
Two quantities describe magnetic fields: the B-field (magnetic flux density) and the H-field (magnetic field strength or intensity). Understanding their difference is crucial for proper unit conversion.
The B-field (measured in Tesla or Gauss) represents the total magnetic flux density, including contributions from both external sources and the material's own magnetization. It is the field that exerts forces on moving charges and current-carrying wires.
The H-field (measured in Amperes per meter or Oersteds) represents the externally applied magnetic field strength, independent of the material's response. In vacuum, B = µ₀H, where µ₀ is the permeability of free space. In materials, B = µ₀(H + M), where M is the magnetization.
Our converter focuses on B-field units (Tesla, Gauss, etc.) since these are most commonly needed in practical applications. The H-field requires knowledge of material properties for conversion to B-field values.
Applications of Magnetic Field Measurements
Medical Imaging (MRI)
Magnetic Resonance Imaging uses powerful magnetic fields (typically 1.5T to 3T for clinical systems, up to 11.7T for research) to align hydrogen nuclei in the body. The strength and uniformity of these fields directly affect image quality. MRI technicians and physicists regularly convert between Tesla and Gauss when calibrating equipment and discussing field specifications.
Electric Motors and Generators
Electric motors convert electrical energy to mechanical motion using magnetic fields. Motor designers work with flux densities typically ranging from 0.5T to 2T in the air gap and core. Understanding these values in different unit systems is essential when sourcing components from international suppliers.
Audio Speakers and Microphones
Loudspeakers use permanent magnets (typically 1-2 Tesla in the gap) to convert electrical signals into sound. Speaker engineers specify magnet strength in both Tesla and Gauss depending on the market and supplier conventions.
Earth Science and Navigation
Earth's magnetic field ranges from about 25 to 65 µT (0.25 to 0.65 Gauss) at the surface. Geophysicists studying paleomagnetism, magnetic anomalies, and space weather use nanoTesla and Gamma units. Navigation systems and compass calibration require precise knowledge of local field values.
Earth's Magnetic Field
Earth's magnetic field, also called the geomagnetic field, is generated by convection currents in the liquid iron outer core. This field extends from the interior out into space, forming the magnetosphere that shields us from solar wind and cosmic radiation.
At Earth's surface, the field strength varies from approximately 25 µT near the equator to 65 µT near the magnetic poles. In Gauss, this is 0.25 G to 0.65 G. The field has both horizontal and vertical components, with the total field vector dipping toward the Earth at mid-latitudes.
For context, Earth's field is roughly 100 times weaker than a typical refrigerator magnet (about 5 mT) and 30,000 to 60,000 times weaker than a clinical MRI machine (1.5T to 3T).
Magnetic Field Conversion Table
| Unit | Symbol | Equivalent in Tesla | Equivalent in Gauss |
|---|---|---|---|
| Tesla | T | 1 | 10,000 |
| Gauss | G | 10⁻⁴ | 1 |
| MilliTesla | mT | 10⁻³ | 10 |
| MicroTesla | µT | 10⁻⁶ | 0.01 |
| NanoTesla | nT | 10⁻⁹ | 10⁻⁵ |
| Weber/m² | Wb/m² | 1 | 10,000 |
| Gamma | γ | 10⁻⁹ | 10⁻⁵ |
| MilliGauss | mG | 10⁻⁷ | 10⁻³ |
How to Use the Magnetic Field Converter
- Enter the magnetic field value you want to convert in the input field.
- Select the source unit from the dropdown (Tesla, Gauss, mT, µT, nT, Wb/m², etc.).
- View the instantly calculated results in all supported magnetic field units.
The converter handles both very large values (superconducting magnets at 10+ Tesla) and very small values (geomagnetic measurements in nanoTesla) with full scientific precision.
Frequently Asked Questions
How many Gauss are in one Tesla?
One Tesla equals 10,000 Gauss. The Tesla (T) is the SI unit of magnetic flux density, while the Gauss (G) is the CGS unit. The conversion is straightforward: 1 T = 10⁴ G. This means a 1.5T MRI machine produces a field of 15,000 Gauss.
What is the difference between B-field and H-field?
The B-field (magnetic flux density) is measured in Tesla and represents the total magnetic field including the material's response. The H-field (magnetic field strength) is measured in Amperes per meter (A/m) and represents the external applied field. They are related by B = µH, where µ is the permeability of the material.
What is Earth's magnetic field strength?
Earth's magnetic field strength varies between approximately 25 to 65 microtesla (µT) or 0.25 to 0.65 Gauss at the surface. It is strongest near the magnetic poles and weakest near the equator. In nanoTesla, the range is 25,000 to 65,000 nT.
What units are used for magnetic field measurement?
The primary units include Tesla (T) as the SI unit, Gauss (G) as the CGS unit, milliTesla (mT), microTesla (µT), nanoTesla (nT), Weber per square meter (Wb/m² = Tesla), and Gamma (1 Gamma = 1 nT). MRI machines and particle physics use Tesla, while geophysics often uses nanoTesla.
How strong is an MRI magnetic field?
Clinical MRI machines typically operate at 1.5 Tesla or 3 Tesla, which equals 15,000 or 30,000 Gauss respectively. Research MRI systems can reach 7 Tesla or higher. For comparison, a refrigerator magnet is about 5 milliTesla (50 Gauss), and Earth's field is about 50 µT (0.5 Gauss).
Is Weber per square meter the same as Tesla?
Yes, 1 Weber per square meter (Wb/m²) is exactly equal to 1 Tesla. The Weber is the SI unit of magnetic flux, and when divided by area (m²), it gives the magnetic flux density in Tesla. They are dimensionally and numerically identical.
Why do some industries still use Gauss instead of Tesla?
The Gauss unit remains widely used in the United States due to historical precedent and because Gauss values are often more convenient for everyday magnetic field strengths. Many Gaussmeters, instruments, and product specifications still use Gauss. Additionally, consumer-level fields (magnets, speakers) have more intuitive numbers in Gauss.
What magnetic field strength is dangerous to humans?
Static magnetic fields below about 4 Tesla are generally considered safe for short-term exposure. However, fields above 0.5 mT (5 Gauss) can interfere with pacemakers and medical implants. MRI safety guidelines limit occupational exposure, and fields above 8 Tesla may cause sensory effects like vertigo and metallic taste.