Magnetic Flux Calculator

Magnetic flux measures how much of a magnetic field passes through a surface — a core concept in electrical engineering, motor design, and electromagnetic induction. Enter your Magnetic Field (B), Area (A), Angle (θ), and Number of Turns (N) into the Magnetic Flux Calculator to get the Magnetic Flux (Φ) in Webers. Secondary outputs include Flux Density and Total Flux accounting for all coil turns. Also try the use the Volt to Electron Volt Calculator.

T

Strength of magnetic field in Tesla

m²

Surface area through which flux passes

°

Angle between magnetic field and surface normal (0° = perpendicular)

Number of coil turns (1 for single surface)

Results

Magnetic Flux (Φ)

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Flux Density

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Total Flux (with turns)

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Frequently Asked Questions

What is magnetic flux and how is it calculated?

Magnetic flux (Φ) is the total magnetic field passing through a surface. It's calculated using the formula Φ = B × A × cos(θ), where B is magnetic field strength in Tesla, A is the area in square meters, and θ is the angle between the field and surface normal. See also our Coulomb's Law Calculator.

What happens when the magnetic field is perpendicular to the surface?

When the magnetic field is perpendicular to the surface (θ = 0°), cos(0°) = 1, so the flux is maximum: Φ = B × A. This gives the highest possible flux value for the given field strength and area.

What units are used for magnetic flux?

Magnetic flux is measured in webers (Wb). One weber equals one Tesla-meter squared (T⋅m²). The magnetic field is measured in Tesla (T) and area in square meters (m²).

How does the angle affect magnetic flux calculation?

The angle θ is measured between the magnetic field direction and the normal (perpendicular) to the surface. As the angle increases from 0° to 90°, the flux decreases according to cos(θ). At 90°, the flux becomes zero. You might also find our Dipole Moment Calculator useful.

What is the difference between magnetic flux and flux density?

Magnetic flux density (B) is the magnetic field strength per unit area, measured in Tesla. Magnetic flux (Φ) is the total field passing through a surface, measured in webers. Flux = flux density × area × cos(angle).

How do multiple turns in a coil affect magnetic flux?

For a coil with N turns, the total flux linkage is N × Φ, where Φ is the flux through one turn. This is important in electromagnetic induction calculations where each turn contributes to the total induced EMF.

What are typical magnetic field strengths to use in calculations?

Earth's magnetic field is about 25-65 μT (0.000025-0.000065 T), refrigerator magnets are around 0.001-0.01 T, MRI machines use 1.5-3 T, and superconducting magnets can reach 10+ T. Laboratory electromagnets typically range from 0.1-2 T.