Magnetic Field Conversion Calculator

The Ultimate Guide to Magnetic Field Conversions

Magnetism is one of the fundamental forces of nature, responsible for everything from the Earth's protective magnetic shield to the operation of electric motors and MRI machines. When studying or working with magnetism, it's crucial to use precise units of measurement. However, the field of electromagnetism uses several different units, which can be confusing. Our Magnetic Field Conversion Calculator is designed to simplify this by providing instant, accurate conversions for the most common units of magnetic fields.

How to Use the Magnetic Field Converter

Our tool is divided into two independent sections for the two types of magnetic fields. Conversions happen in real-time within each section.

1. Choose a Category: Decide if you are converting a unit of Magnetic Flux Density (B-field) or Magnetic Field Strength (H-field).
2. Select an Input Unit: Choose the field corresponding to the unit you are starting with (e.g., if you have a magnet's strength in Gauss, use that box).
3. Enter Your Value: Type the number into the selected field.
4. View Instant Conversions: As you type, all other fields *within that same category* will immediately update to show the equivalent value.

B-Field vs. H-Field: A Critical Distinction

One of the most confusing aspects of magnetism is the existence of two different "magnetic fields": the B-field and the H-field. While closely related, they represent different aspects of magnetism.

• Magnetic Field Strength (H): This field is generated by moving electric charges (currents) and magnetic dipoles. It can be thought of as the "cause" of magnetism. It is measured in Amperes per meter (A/m) in the SI system.
• Magnetic Flux Density (B): This field, also known as magnetic induction, represents the resulting magnetic field within a material after it responds to the H-field. It measures the density of magnetic field lines. It can be thought of as the "effect." It is measured in Tesla (T) in the SI system.

In a vacuum, the B and H fields are directly proportional (B = μ₀H, where μ₀ is the permeability of free space). However, inside magnetic materials, the relationship is more complex (B = μH), as the material itself contributes to the total magnetic field.

Units of Magnetic Flux Density (B)

• Tesla (T): The Tesla is the official SI unit of magnetic flux density. One Tesla represents a very strong magnetic field. For context, the Earth's magnetic field is about 0.00005 T, while the powerful magnets in an MRI machine can be 1.5 to 3 T.
• Millitesla (mT): A millitesla is one-thousandth of a Tesla (1 T = 1,000 mT). It's a more convenient unit for measuring weaker magnetic fields.
• Gauss (G): The Gauss is the corresponding unit in the older CGS (centimeter-gram-second) system. It is much smaller than a Tesla: 1 Tesla = 10,000 Gauss. Gauss is still commonly used to describe the strength of permanent magnets, like refrigerator magnets.

Units of Magnetic Field Strength (H)

• Amperes per meter (A/m): This is the SI unit of magnetic field strength. It is derived from the definition of the H-field being generated by electric currents.
• Oersted (Oe): The Oersted is the CGS equivalent, named after Hans Christian Ørsted, who discovered the connection between electricity and magnetism. One Oersted is approximately 79.577 A/m.

Frequently Asked Questions (FAQ)

What is the difference between Magnetic Flux Density (B-field) and Magnetic Field Strength (H-field)?

Magnetic Field Strength (H) is the force generated by currents and magnets, essentially the 'cause' of a magnetic field. Magnetic Flux Density (B) is the resulting 'effect'—it measures the density of magnetic field lines and how the material responds to the H-field. In a vacuum, B and H are directly proportional, but in materials, the relationship is more complex (B = μH, where μ is the permeability of the material).

What is a Tesla (T)?

The Tesla (T) is the SI unit for Magnetic Flux Density (B-field). It is a measure of the strength of a magnetic field. One tesla is a relatively large unit; the Earth's magnetic field is about 50 microteslas, while an MRI machine can generate fields of 1.5 to 3 teslas.

Which is stronger, a Tesla or a Gauss?

A Tesla is much stronger than a Gauss. One Tesla is equal to 10,000 Gauss. Gauss is the older CGS (centimeter-gram-second) unit for magnetic flux density and is still commonly used for measuring the strength of permanent magnets.