Calculator Inputs
The page keeps a single main flow, while the calculator fields switch into responsive columns on larger screens.
Example Data Table
| Scenario | Inputs | Calculated μ | Calculated μr | Calculated B |
|---|---|---|---|---|
| Direct field example | B = 1.20 mT, H = 900 A/m | 1.333333e-6 H/m | 1.061033 | 1.200000e-3 T |
| Relative permeability example | μr = 1500, H = 250 A/m | 1.884956e-3 H/m | 1500 | 0.471239 T |
| Inductance ratio example | Lcore = 75 mH, Lair = 0.5 mH | 1.884956e-4 H/m | 150 | Derived if H is provided |
| Magnetic circuit example | ℜ = 450000 A/Wb, l = 0.18 m, A = 2.5 cm² | 1.600000e-3 H/m | 1273.240 | Derived if H is provided |
These rows are illustrative calculation examples. They are useful for testing the form and reviewing expected output style.
Formula Used
Direct field method: μ = B / H
Relative permeability: μr = μ / μ0
Susceptibility relation: χm = μr − 1
From relative permeability: μ = μ0μr
From susceptibility: μr = 1 + χm
Flux density estimate: B = μH
Inductance ratio estimate: μr ≈ Lcore / Lair
Magnetic circuit estimate: μ = l / (ℜA)
The calculator assumes a linear, isotropic response. Real materials can show saturation, hysteresis, anisotropy, temperature drift, and frequency-dependent behavior.
How to Use This Calculator
- Select the method that matches your known data.
- Enter values using the unit menus beside each field.
- Choose the decimal precision you want for results.
- Press Calculate Permeability to generate the report.
- Review μ, μr, χm, B, H, and the plotted B-H line.
- Download the result summary as CSV or PDF when needed.
Frequently Asked Questions
1. What does magnetic permeability measure?
Magnetic permeability measures how easily a material supports magnetic field formation. Higher permeability usually means stronger magnetic response for the same applied field strength.
2. What is the difference between μ and μr?
μ is the absolute permeability in H/m. μr is the ratio of a material’s permeability to vacuum permeability, so it is unitless.
3. When should I use the direct B and H method?
Use the direct method when you already know flux density and magnetic field strength. It is the most straightforward approach for measured field data.
4. Is the inductance ratio method exact?
It is an approximation. It works best when coil geometry and test conditions stay the same between air-core and magnetic-core measurements.
5. Why can real materials differ from the graph?
The graph assumes a linear B-H relationship. Ferromagnetic materials often become nonlinear, especially near saturation or under changing frequency conditions.
6. Can this calculator handle diamagnetic materials?
Yes. If susceptibility is negative but still greater than minus one, the calculator can estimate a permeability below free-space permeability.
7. What units are supported here?
The calculator supports Tesla, millitesla, gauss, A/m, kA/m, oersted, several inductance units, and multiple geometry units for magnetic circuits.
8. Why export results as CSV or PDF?
CSV is useful for spreadsheets and lab records. PDF is useful for sharing a clean report with students, clients, or colleagues.