Flux Density Calculator

Measure field strength fast, accurate, and responsive online. Switch formulas, units, and angles easily here. See the answer above, then refine inputs confidently now.

Calculator
Choose a method, enter values, and submit.
Pick B for magnetic fields, D for electric displacement.
Method list adapts to your selected flux type.
0–10 supported. Default is 4.
Result appears above this form.

Inputs for B = Φ / A

Inputs for B = F / (I · L · sinθ)
Use 90° when the wire is perpendicular to the field.

Inputs for B = F / (|q| · v · sinθ)

Inputs for B = μ0 · μr · H
Use 1 for vacuum or air (approx.).
Unit is A/m.
Constants used
μ0 = 4π×10⁻⁷ H/m

Inputs for D = Q / A

Inputs for D = ε0 · εr · E
Constant used
ε0 = 8.854187817×10⁻¹² F/m

Example data table

These examples show typical inputs and the resulting flux density.

Flux type Method Inputs (sample) Output
Magnetic (B) Φ / A Φ = 12 mWb, A = 0.004 m² B = 3 T
Magnetic (B) Wire force F = 0.18 N, I = 2.5 A, L = 0.35 m, θ = 90° B ≈ 0.206 T
Magnetic (B) μ0 μr H μr = 2000, H = 800 A/m B ≈ 2.011 T
Electric (D) ε0 εr E εr = 2.2, E = 3.5 kV/m D ≈ 6.82×10⁻⁸ C/m²

Formulas used

Magnetic flux density (B)
  • B = Φ / A (uniform field across area)
  • B = F / (I · L · sinθ) (wire in a field)
  • B = F / (|q| · v · sinθ) (moving charge)
  • B = μ0 · μr · H (material response)
Electric flux density (D)
  • D = Q / A (uniform surface charge density)
  • D = ε0 · εr · E (linear dielectric)

How to use this calculator

  1. Select the flux type (magnetic B or electric D).
  2. Pick a method that matches your known measurements.
  3. Enter values and choose units for each input.
  4. Optionally enable steps and extra unit outputs.
  5. Press Submit and review the result above the form.
  6. Use Download CSV or Download PDF to save the report.
Reminder: θ is the angle between the direction and the field.

FAQs

1) What is flux density in simple terms?

It describes how strongly a field passes through a given area. Magnetic flux density B is in tesla, and electric flux density D is in coulombs per square meter.

2) Which method should I choose for magnetic calculations?

Use Φ/A when you know flux and area. Use wire-force when you measured force, current, length, and angle. Use Lorentz when you know force on a moving charge. Use μr and H for material-based fields.

3) Why does the angle θ matter in some formulas?

Only the component perpendicular to the field contributes. That is why sinθ appears. If θ is 0° or 180°, sinθ becomes zero and the calculation cannot be performed.

4) What units does the calculator support?

It supports common units for flux, area, force, length, current, charge, velocity, and electric field. Results can be displayed in multiple unit scales when “Show extra units” is enabled.

5) Can this be used for non-uniform fields?

The Φ/A approach assumes uniform field over the area. If the field varies significantly, you need an integral approach to compute flux first, then interpret an average density over the surface.

6) Why do my results look extremely large or small?

Check your unit choices and scaling. Micro, milli, and kilo factors can shift results by orders of magnitude. Also verify angles and that your area or length values are not unintentionally tiny.

7) Is gauss the same as tesla?

They measure the same quantity but on different scales. One tesla equals ten thousand gauss. The calculator can show both when extra units are enabled.

8) How do the CSV and PDF exports work?

After a successful calculation, the page saves your latest inputs and outputs. The export buttons generate a structured CSV or a simple one-page PDF report using that saved result.

Note: This tool is for learning and estimation. For high-precision work, confirm assumptions and measurement accuracy.

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