Calculate pull force, flux density, and coil fields. Switch methods easily and test realistic scenarios. See clean outputs, graphs, exports, examples, and guidance instantly.
| Method | Sample Inputs | Sample Output |
|---|---|---|
| Pull Force to Field | 120 N, 15 cm², μr = 1 | 0.448399 T, 448.399297 mT |
| Dipole Field on Axis | 3.5 A·m², 4 cm, μr = 1 | 0.010938 T, 10.937500 mT |
| Dipole Field on Equator | 3.5 A·m², 4 cm, μr = 1 | 0.005469 T, 5.468750 mT |
| Solenoid Field | 2.4 A, 600 turns, 18 cm, μr = 200 | 2.010619 T, 2010.619298 mT |
This calculator supports several magnet strength models because magnet strength can mean holding force, field intensity, or coil-generated field. Each method estimates a different physical quantity from the inputs you provide.
For a magnet pulling across a small air gap, magnetic pressure is estimated by:
F = (B² × A) / (2μ)
Rearranging gives:
B = √(2μF / A)
Here, F is pull force, A is contact area, μ = μ0μr, and B is magnetic flux density.
For a dipole on its axis:
B = (μ0μr / 4π) × (2m / r³)
For the equatorial line:
B = (μ0μr / 4π) × (m / r³)
Here, m is magnetic moment and r is distance from the dipole center.
For a long solenoid:
H = nI
B = μH = μ0μr nI
Here, n is turns per meter, I is current, and μr represents the core material effect.
The calculator also reports field strength H, energy density u, and magnetic flux Φ where applicable:
H = B / μ
u = B² / (2μ)
Φ = B × A
These formulas are idealized. Real magnets vary with geometry, air gap, material saturation, temperature, leakage flux, and manufacturing tolerances.
Select the method that matches your problem first. Use Pull Force to Field when you know holding force and area. Use a Dipole option when you know magnetic moment and distance. Use Solenoid Field for coils with current, turns, and length.
Enter every value in the form grid. Choose the matching units for force, area, distance, current, and length. The calculator converts everything internally to SI units before solving.
Relative permeability affects the magnetic field estimate. For air, a value near 1 is common. Ferromagnetic cores can be much larger, but real values change with operating conditions.
After submitting, the result appears above the form. Review the output table for Tesla, milliTesla, Gauss, magnetic field strength, flux, pressure, and other derived quantities. Then inspect the Plotly graph to see how the chosen variable changes the field or force.
Use the CSV button when you want a simple data export. Use the PDF button when you want a quick printable report. The example table below the form helps you verify that your entries follow the expected pattern.
Magnet strength is not one universal number. Engineers often describe strength by flux density, holding force, magnetic moment, field gradient, or energy density. Because applications differ, this page combines several useful models inside one interface.
Pull force is useful for lifting, clamping, and separation tasks. Flux density in Tesla or Gauss helps compare field intensity. Dipole models help estimate how field decays with distance. Solenoid equations are practical for electromagnets, relays, lab coils, and actuator studies.
Distance matters a lot. In dipole methods, the field changes with the cube of distance. Small spacing changes can create large field changes. Area also matters because the same field over a larger face can produce more force.
Always treat idealized results as engineering estimates. Real systems may include fringing, nonuniform poles, curved air gaps, temperature shifts, and core saturation. When accuracy matters, validate with measured data, manufacturer curves, or finite element analysis.
It can mean holding force, flux density, field strength, or coil output. This calculator lets you estimate each one with a suitable model.
Tesla measures magnetic flux density. It is one common way to express field intensity, but not the only way people describe magnet strength.
In the dipole models, field scales with 1/r³. Doubling the distance reduces the field sharply, which is why spacing is critical.
Use values above 1 for magnetic materials or core-based estimates. For air and most open-space approximations, use a value near 1.
Actual force depends on pole shape, surface finish, gap size, alignment, leakage flux, and saturation. The formula assumes a simplified magnetic circuit.
B is flux density in Tesla. H is magnetic field strength in A/m. They are related through permeability.
Yes. The solenoid mode is designed for electromagnets, especially when you know turns, current, coil length, and core permeability.
No. It is best for planning, learning, and preliminary design. Final validation should come from measurement or a detailed simulation workflow.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.