How to Use Flux Calculator
The Flux Calculator computes the flux through a flat surface in seconds.
- Select Flux Type — Choose Magnetic Flux to work with magnetic fields (B in Tesla), or Electric Flux to work with electric fields (E in N/C).
- Enter Field Strength — Type the magnitude of the uniform field. Use SI units: Tesla for B, or N/C for E.
- Enter Surface Area — Type the area in square metres (m²).
- Enter the Angle and Unit — Enter the angle θ between the field direction and the surface normal. Choose Degrees or Radians. The Flux Calculator accepts both and converts internally.
- Read the Results — The Flux Calculator displays the flux value, the formula used, and a step-by-step substitution showing every value substituted into the formula.
A contextual note appears when θ = 0° (maximum flux) or θ = 90° (zero flux) to help you understand the geometric meaning.
Formula & Theory - Flux Calculator
The Flux Calculator applies the standard physics formula for flux through a uniform field:
Magnetic Flux: Φ_B = B × A × cos(θ)
Electric Flux: Φ_E = E × A × cos(θ)| Symbol | Meaning | Unit |
|---|---|---|
| Φ_B | Magnetic flux | Weber (Wb = T·m²) |
| Φ_E | Electric flux | N·m²/C |
| B | Magnetic field strength | Tesla (T) |
| E | Electric field strength | N/C or V/m |
| A | Surface area | m² |
| θ | Angle between field and surface normal | degrees or radians |
Effect of Angle
The cosine term is what makes flux depend on orientation:
θ = 0° → cos(0°) = 1 → Φ = B × A (maximum, field ⊥ surface)
θ = 90° → cos(90°) = 0 → Φ = 0 (zero, field ∥ surface)
θ = 180° → cos(180°) = −1 → Φ = −B × A (reversed direction)In many physics problems, the negative sign for θ > 90° indicates that field lines exit rather than enter the surface.
Assumptions and Limits
The Flux Calculator assumes a uniform field of constant magnitude passing through a flat (planar) surface. For curved surfaces or non-uniform fields, calculus-based surface integrals are required. Results are exact within floating-point precision for inputs within the normal SI engineering range.
Use Cases for Flux Calculator
The Flux Calculator is useful across physics education, electrical engineering, and electromagnetism coursework:
- Classroom Practice — Verify homework answers for electromagnetic induction and Gauss’s Law problems using the Flux Calculator.
- Coil and Transformer Design — Estimate the magnetic flux through a coil’s cross-sectional area to check whether Faraday induction thresholds are met.
- Sensor Calibration — Compute expected magnetic flux through Hall-effect sensors given known field strength and tilt angle.
- Gauss’s Law Problems — Calculate electric flux through a Gaussian surface for textbook problems without manual trigonometry.
- Angle Sensitivity Analysis — Adjust θ in the Flux Calculator to see how even small misalignments reduce flux, which is critical for antenna and panel orientation.