Magnetic Field Calculator

When electric current flows through a wire, it generates a surrounding magnetic field — the Magnetic Field Calculator computes exactly how strong that field is based on your wire's geometry and material. Enter your current (I), distance from the wire (d), and relative permeability, then select a wire configuration — straight wire, circular loop, or solenoid — to get the Magnetic Field Strength (B) in Tesla. Secondary outputs include the field in Gauss and the Magnetic Field Intensity (H) in A/m.

A

Electric current flowing through the wire

m

Perpendicular distance from the wire center

Material permeability relative to free space

m

Required for circular loop calculations

Number of wire turns (for solenoid)

Results

Magnetic Field Strength (B)

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Magnetic Field (Gauss)

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Magnetic Field Intensity (H)

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Frequently Asked Questions

How is the magnetic field calculated around a wire?

The magnetic field around a straight current-carrying wire is calculated using Ampère's law: B = (μ₀ × μᵣ × I) / (2π × d), where μ₀ is the permeability of free space, μᵣ is relative permeability, I is current, and d is distance from the wire.

What is the difference between Tesla and Gauss units?

Tesla (T) is the SI unit for magnetic field strength, while Gauss (G) is the CGS unit. The conversion is: 1 Tesla = 10,000 Gauss. Tesla is commonly used in scientific applications, while Gauss is often used for smaller magnetic fields.

How does distance affect magnetic field strength?

Magnetic field strength decreases inversely with distance from the wire. This means doubling the distance reduces the field strength by half. The relationship is linear and follows the 1/r dependency for straight wires.

What is relative permeability and how does it affect calculations?

Relative permeability (μᵣ) describes how a material affects magnetic field strength compared to free space. Air and vacuum have μᵣ = 1, ferromagnetic materials have much higher values, while diamagnetic materials have slightly less than 1.

Can this calculator handle different wire configurations?

Yes, the calculator supports straight wires, circular loops, and solenoids. Each configuration uses different formulas: straight wires use Ampère's law, loops use the Biot-Savart law at the center, and solenoids use the formula for magnetic field inside a coil.

How accurate are the magnetic field calculations?

The calculations are based on theoretical formulas and assume ideal conditions (infinite straight wire, perfect circular loops, etc.). Real-world results may vary due to wire thickness, nearby magnetic materials, and finite wire length.

What is the relationship between current and magnetic field?

Magnetic field strength is directly proportional to the electric current. Doubling the current doubles the magnetic field strength, assuming all other parameters remain constant. This linear relationship makes it easy to scale calculations.