Magnetic Flux Calculator
Enter flux density, area and angle to compute the magnetic flux Φ = B·A·cosθ in webers (and maxwells).
Input Data
Results
At a glance:Magnetic flux Φ measures the total magnetic field passing through a surface: Φ = B·A·cosθ, where B is the magnetic flux density (tesla), A the area and θ the angle between B and the surface normal. It is measured in webers (Wb = T·m²); 1 maxwell = 10⁻⁸ Wb. Maximum flux occurs when the field is perpendicular to the surface (θ=0, cosθ=1); zero when parallel (θ=90°). Faraday's law uses the rate of change of flux: ε = −N·dΦ/dt. Flux is also the integral of B over area: Φ = ∫B·dA. This tool returns Φ in Wb, mWb and maxwells.
Formula
Φ = B·A·cosθ
1 Wb = 10⁸ maxwells
Faraday: ε = −N·dΦ/dt
$$\Phi = \mathbf{B} \cdot \mathbf{A} = B\,A\,\cos\theta$$How to Use
- Enter flux density B (T).
- Enter area A (m²) and angle θ (°).
- The calculator returns Φ in Wb, mWb and maxwells.
Case Studies
Coil flux
B = 0.5 T, A = 0.02 m², θ = 0.
Φ = 0.5×0.02×1 = 0.01 Wb = 10 mWb.
10⁶ maxwells.
FAQ
Why cosθ?
Only the component of B perpendicular to the surface contributes to flux; cosθ projects B onto the normal. At θ=90° (field parallel to surface) no flux passes through.
What is a weber?
The SI unit of magnetic flux: 1 Wb = 1 T·m² = 10⁸ maxwells (CGS). It is the flux that, linking a one-turn coil and changing at 1 Wb/s, induces 1 V.
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References
Content review: Calculatorism Editorial Team. Results are for reference only; please refer to the relevant authorities for the official figures.