The attraction and repulsion associated with permanent magnets are among their most familiar and directly observable characteristics. This naturally leads to a practical question: how much force can magnets produce when interacting with another magnet or a ferromagnetic counterpart?

Pull force provides a convenient numerical value for comparing magnets and supporting preliminary product selection. However, it is not a fixed property determined by magnet grade or dimensions alone. The reported value also depends on the counterpart, contact conditions, magnetic circuit, and calculation or test method.

The calculators below provide preliminary pull force estimates for cylinder, block, and ring magnets under simplified conditions. The results are useful for initial comparison, but they should not be interpreted as actual load capacity without considering the complete application.

Pull Force Calculator for Cylinder Shape

Pull Force Calculator for Block Shape

Pull Force Calculator for Ring Shape

Calculation Notes and Assumptions

These calculators provide preliminary estimates of direct pull force under idealized zero-gap conditions.
The calculation model assumes either two identical magnets with opposite poles facing and accurately aligned, or one magnet in full contact with a sufficiently large, thick, and magnetically unsaturated steel plate. These two configurations are treated as equivalent within the simplified calculation model, although actual measured forces may differ.
Pull force is assumed to act perpendicular to the contact surfaces and through the center of the magnets. The contacting surfaces are assumed to be flat, parallel, clean, and in full contact.
Calculations are based on nominal magnetic properties and ideal magnet dimensions. Coatings, chamfers, dimensional tolerances, surface roughness, misalignment, temperature, surrounding magnetic components, and variations in magnetization or steel properties are not included.
Results should be used for preliminary comparison only. Magnets should be tested in the actual configuration before pull force values are used for design or load-capacity decisions.

What Does Magnetic Pull Force Mean?

Magnetic pull force is the maximum force required to separate magnets from a defined counterpart under specified conditions. It is also commonly described as breakaway force or separation force.

Pull force generally refers to separation in a direction perpendicular to the contact surfaces. Magnets and counterparts are aligned, and loads are applied through the center of the contact area. This differs from lateral sliding or peeling, where loads act in different directions or cause contact surfaces to separate progressively from one edge.

Pull force is not an intrinsic material property. It describes the interaction of complete magnetic systems and therefore depends on magnet material, geometry, pole area, air gap, counterpart properties, and test configuration. Pull force values are meaningful only when these conditions are clearly defined.

How Magnetic Pull Force Is Measured?

Magnetic pull force is measured by gradually increasing the tensile load between magnets and defined counterparts until the magnetic contact separates. The highest force recorded immediately before separation is normally reported as breakaway force or pull force.

The test method published by the Magnet Distributors and Fabricators Association provides a useful industry reference for perpendicular separation, test plates, controlled loading, and peak-force recording. However, it does not fully standardize how different magnets should be connected to force-measuring equipment. This is important because testing systems measure forces transmitted through the complete load path, rather than only the magnetic force at contact surfaces.

The Load Path and Specimen Fixture

A typical load path includes the testing machine, load cell, connecting components, specimen fixture, magnet, and counterpart. Every part of this load path must remain stable until magnetic separation occurs.

For results to represent magnetic pull force, separation must occur between magnet working surfaces and counterparts. Results should not be treated as valid pull force measurements when magnets detach from adhesives, connecting parts fail, fixtures bend, or specimens rotate and begin to peel away from one edge.

Cylinder, block, and ring magnets generally require rigid, non-magnetic fixtures. Working pole surfaces should remain fully exposed, while magnets are restrained from non-working surfaces or sides. Pulling axes should pass through the centers of magnetic contact areas, and fixtures should prevent rotation, lateral movement, and uneven separation.

Adhesives may be used to connect magnets to fixtures when mechanical fixing is impractical. However, adhesive joints must withstand forces well above the expected breakaway forces and remain intact throughout testing. If adhesive failure occurs before magnetic separation, the recorded value represents failure of the fixture connection rather than magnetic pull force.

Typical Pull Force Test Equipment

Controlled pull force measurements are commonly performed with universal testing machines or motorized test stands. A typical system includes:

a calibrated load cell or digital force gauge;
a rigid, non-magnetic specimen fixture;
an alignment mechanism for perpendicular loading;
a defined test plate or other counterpart;
and peak-force recording.

Load cell capacity should be appropriate for expected pull force. Sensors selected for loads far above the measurement range may not provide sufficient resolution for smaller magnets.

Motorized movement generally provides more consistent pulling speed than manual testing. Test plates are commonly made from low-carbon steel and should be sufficiently large and thick to avoid limiting results through edge effects or magnetic saturation. Plate material, dimensions, flatness, surface finish, and condition should be clearly defined.

Test Procedure and Result Validation

Magnet working surfaces and counterparts should be clean, flat, and fully seated before loading begins. Pulling axes should be perpendicular to contact surfaces and pass through the centers of magnetic contact areas.

Loads should be increased gradually at a controlled speed until complete separation occurs. Peak force immediately before separation should be recorded, and tests should be repeated after repositioning specimens to evaluate consistency.

During testing, operators should confirm that:

specimens remain aligned;
fixtures do not bend or rotate;
magnetic contact separates at the intended interface;
adhesives and mechanical connections remain intact;
and no lateral sliding or peeling occurs before breakaway.

Force-displacement data may also be recorded when information about force across increasing separation distances is required.

Alternative Methods and Reporting Conditions

Manual force gauges can be used for field checks or basic comparisons, but pulling angle, speed, and operator technique may reduce repeatability.

Calibrated weights can be used for proof-load or threshold testing. Supporting a specified weight demonstrates that breakaway force exceeds that static load under the tested conditions, but it does not determine the exact peak pull force. Weight increments, swinging, and impact loading can further reduce accuracy.

Pull force results should be reported together with the relevant test conditions, including:

magnet material, dimensions, and magnetization direction;
whether specimens are bare magnets or complete assemblies;
counterpart material, dimensions, thickness, and surface condition;
contact condition and air gap;
specimen fixture and loading interface;
pull direction, speed, and alignment;
load cell range;
test temperature;
number of repetitions;
and the observed location and mode of separation.

Without these conditions, results obtained from different tests or suppliers may not be directly comparable.

Even well-controlled pull force values represent defined test configurations rather than allowable working loads. Complete assemblies should retain appropriate design margins and be validated under representative operating conditions before use.

What Determines Magnetic Pull Force?

Magnetic pull force is determined by magnets, counterparts, and the conditions at their contact surfaces. Magnet material and dimensions are important, but they do not determine pull force independently. Counterpart properties, air gaps, alignment, load direction, temperature, and nearby magnetic materials can all affect the result.

Magnet Material and Geometry

Within the same material family, higher magnet grades generally produce greater pull force when dimensions, magnetization patterns, and test conditions remain unchanged. Across different materials, however, remanence or maximum energy product alone is not sufficient for comparison. The usable magnetic output also depends on the demagnetization curve and the operating point established by magnet geometry and the external magnetic circuit.

Larger effective pole areas generally increase total pull force when sufficient flux density can be maintained and counterparts are not magnetically saturated. Increasing magnet thickness can also improve pull force, although the additional benefit gradually decreases. Holes, chamfers, dimensional proportions, and magnetization patterns can therefore cause magnets with similar material volumes to produce different pull forces.

Counterpart Material, Size, and Thickness

When magnets are attached to ferromagnetic counterparts, the counterparts become part of the magnetic circuit and influence how magnetic flux is distributed around the contact area. Their permeability, composition, thickness, size, and geometry can therefore affect pull force.

Thin or undersized steel plates may become magnetically saturated or provide insufficient cross-sectional area for carrying magnetic flux, limiting the force that can be developed. Counterparts should generally extend beyond magnet working surfaces and be sufficiently thick for the expected magnetic flux.

Different steel grades may produce different results even when their dimensions are identical. Stainless steels and other materials should not be assumed to provide the same magnetic response as low-carbon steel.

Air Gaps and Contact Surfaces

Pull force decreases rapidly as the distance between magnets and counterparts increases. Coatings, paint, adhesive layers, protective films, dirt, corrosion, roughness, and assembly clearances can all create effective air gaps.

Even when components appear to be in contact, uneven or curved surfaces may prevent full-area contact. This is especially important for magnets with larger pole areas, where small variations in flatness can significantly reduce measured pull force.

Alignment and Load Direction

Maximum pull force is generally obtained when working surfaces are fully aligned and loads act perpendicular to the contact area.

Lateral offset reduces the overlapping magnetic area and changes the flux path. Off-center loading can cause one edge to separate first, creating peeling rather than uniform perpendicular separation. Much lower forces may then be sufficient to release the magnet.

Pull force values should therefore not be used directly to predict lateral sliding resistance, peeling resistance, or performance under combined loads.

Temperature and Nearby Magnetic Materials

Magnetic properties change with temperature, and pull force generally decreases as magnet temperature rises. Test temperature should therefore be recorded. When service temperatures differ significantly from room temperature, pull force should be verified under representative operating conditions or suitable temperature-related allowances should be included in the design.

Nearby steel parts, housings, and other magnets may redirect or redistribute magnetic flux. Magnets tested individually may therefore produce different pull forces after installation, even when the nominal contact surfaces remain unchanged.

Why Pull Force Became a Common Magnet Specification?

Pull force provides a single numerical value that is easy to understand and compare across magnet sizes. Unlike magnetic flux density, magnetic moment, or material properties, it appears to answer a direct practical question: how strongly will the magnet hold?

This makes pull force particularly useful in online magnet catalogs. Products can be sorted by force, similar sizes can be compared quickly, and customers can narrow large numbers of stock items without interpreting magnetic curves or detailed material data. Suppliers with extensive SKU ranges may therefore treat pull force as one of the main performance specifications for each product.

However, the apparent simplicity of the value can hide important differences in calculation methods, test plates, fixtures, air gaps, and reporting conditions. Pull force remains useful for preliminary comparison, but values from different suppliers should not be assumed to be directly equivalent unless the underlying conditions are comparable.

Why Listed Pull Force Is Not Actual Load Capacity?

Listed pull force usually represents peak force under direct, perpendicular separation from a defined counterpart. Actual loads may instead act laterally, eccentrically, dynamically, or through structures that allow sliding or peeling. These conditions can require much less force to release magnets.

A value stated as “50 kg pull force” is also commonly expressed in kilogram-force rather than mass. It indicates a measured or calculated force under specified test conditions, not that a 50 kg object can be safely supported in every orientation or application.

Actual load capacity is determined by the complete application rather than pull force alone. Counterpart properties, effective air gaps, surface condition, load direction, temperature, and dynamic loading can all reduce the usable holding performance available in practice.

Catalog pull force should therefore be treated as a comparison value rather than an allowable working load. Appropriate design margins should be applied, and complete assemblies should be tested under representative load directions, operating conditions, and expected dynamic effects.

When a Pull Force Calculator Is Not Enough?

Analytical pull force calculations are most useful for regular magnet shapes, simple counterparts, uniform air gaps, and direct perpendicular separation. They become less reliable when magnetic flux is strongly influenced by surrounding geometry or when loads do not follow the assumed direction.

Finite element analysis may be required for magnetic assemblies, irregular magnet shapes, thin or shaped steel components, multiple-magnet systems, complex magnetization patterns, nonuniform air gaps, partial overlap, and force-distance evaluation.

Physical testing remains necessary when surface condition, mounting tolerances, friction, deformation, temperature, vibration, impact, or repeated loading affect performance. Final designs should be evaluated as complete assemblies under representative operating conditions rather than relying only on calculated or catalog pull force values.

Discuss Your Magnetic Pull Force Requirements

Pull force calculations can support preliminary magnet selection, but actual performance depends on the complete application. If your project involves specific counterparts, air gaps, load directions, magnetization patterns, or surrounding components, contact us to discuss the magnet design and evaluation requirements.