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Pull Force — Magnetic Pull Force Estimator
Magnetic Engineering

How hard will it pull?

Estimate the holding force of a permanent magnet against a flat steel surface, across block, disk, ring, and sphere geometries. Adjust dimensions, material grade, and air gap to see the pull force update live.

Shape
Material
Dimensions
0.0 mm
Data-calibrated

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0N
0.00 lbf 0.00 kgf
Surface field (B)
0 G (0.000 T)
Pole face area
0.0 mm²
North South Steel target
Pull force vs. air gap
Model & limitations:

All four shapes use force models fit directly to real surface-contact measurements (against a 10mm steel plate) rather than the idealized F = B²A/2μ₀ formula. The formula underestimates real pull force — sometimes by an order of magnitude — because it assumes the on-axis center field applies uniformly across the whole pole face.

The on-axis B field itself matches measurements closely for every shape. Each shape's calibration note (left) gives its fitted range, typical error, and known weak spots. All fits assume the same plate-contact correction applies at any air gap, which is as yet untested beyond zero gap. Treat non-zero-gap results as a rough extrapolation, not a calibrated one.