• Sep 09, 2026

SSKC-016 - Magnet Size vs Magnet Grade: Which One Matters More?

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Magnet Size vs Magnet Grade: Which One Matters More?

Document ID: SSKC-016
Series: Engineering Series
Difficulty: Intermediate
Reading Time: 10–12 minutes
Last Updated: September 2026

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Since 1969, Simple Signman has supplied magnetic materials to Canadian manufacturers, printers, sign professionals, distributors, and industrial businesses.

When customers need more magnetic holding force, one of the first questions is often whether they should choose a higher neodymium grade or simply use a larger magnet.

The answer depends on the complete application.

A higher grade can provide more magnetic energy within the same magnet volume. A larger magnet can change the total magnetic volume, working area, field distribution, and contact area.

In many applications, geometry and size can matter just as much as—or more than—the grade printed on the magnet specification.

Introduction

It is easy to think of neodymium magnet grades as a simple strength ranking:

N35 → N42 → N48 → N52

From that perspective, N52 may appear to be the obvious choice whenever maximum strength is required.

But magnet performance is more complicated.

A small N52 magnet can still produce less total holding force than a larger N35 magnet.

Likewise, increasing magnet thickness may provide useful improvement in one design while increasing diameter or contact area may be more effective in another.

A higher magnet grade does not automatically outperform a larger or better-designed magnet.

The right choice depends on magnet dimensions, geometry, steel thickness, air gap, load direction, available space, and the magnetic circuit.

Contents

What Does Magnet Grade Actually Change?

The grade of a neodymium magnet describes important magnetic properties of the NdFeB material.

Grades such as N35, N42, N48, and N52 are associated with different maximum energy products and magnetic characteristics.

When two magnets have the same:

  • dimensions;
  • shape;
  • magnetization direction;
  • coating;
  • operating conditions;

a higher grade can generally provide a stronger magnetic field and potentially higher holding force.

However, grade does not change the magnet's physical dimensions or contact area.

Engineering Insight

Magnet grade increases the magnetic capability of a given volume. It does not replace the effects of geometry, volume, steel thickness, air gap, and magnetic circuit design.

For more information, see SSKC-005 — Neodymium Magnet Grades Explained.

What Does Magnet Size Actually Change?

Changing magnet size can affect several characteristics at the same time.

Increasing dimensions can change:

  • magnetic volume;
  • working face area;
  • field distribution;
  • working distance;
  • total available magnetic flux;
  • pull force;
  • weight;
  • cost.

A larger magnet does not simply contain “more of the same strength.” Its geometry changes the way the magnetic field interacts with the target.

This is why increasing diameter, increasing thickness, and increasing grade are three different design changes.

N35 vs N52: What Is the Real Difference?

N52 is a higher-energy neodymium grade than N35.

When two magnets have the same geometry, an N52 magnet will generally be magnetically stronger than the equivalent N35 magnet.

But that does not mean an N52 magnet of any size will outperform every N35 magnet.

Simple Example

Compare:

  • a small N52 disc magnet;
  • a much larger N35 disc magnet.

The larger N35 magnet may have substantially more magnetic material and a much larger working surface.

Depending on the application, it can therefore provide more total holding force.

A small N52 magnet can still produce less total holding force than a larger N35 magnet.

Why Magnet Volume Matters

Magnetic material volume is an important part of magnet performance.

Increasing the volume of magnetic material can increase the total magnetic energy available to the system.

For a simple disc magnet, increasing:

  • diameter;
  • thickness;
  • or both

increases the total magnet volume.

However, holding force does not increase according to one universal size-to-force formula.

The result depends on geometry, magnetic circuit, target steel, air gap, and other conditions.

Engineering Insight

When comparing two magnets, consider both the magnetic material grade and the total amount and geometry of magnetic material.

Why Diameter and Face Area Matter

Increasing magnet diameter or working-face dimensions can increase the area over which the magnetic field interacts with the target steel.

This can be particularly useful in direct holding applications.

A larger working face may provide:

  • greater contact area;
  • greater total magnetic interaction with the steel;
  • higher total pull force in suitable conditions;
  • improved load distribution.

However, a larger face also requires an appropriately sized steel target.

If the steel is too thin or too small, the larger magnet may not achieve its full potential.

Why Magnet Thickness Matters

Increasing magnet thickness can also increase magnetic performance.

For example, increasing the thickness of an axially magnetized disc can increase the magnetic field available at the working face.

However, the improvement eventually becomes subject to diminishing returns.

Once the magnet is already sufficiently thick relative to its other dimensions, adding more thickness may produce a smaller benefit than increasing another dimension.

The exact behaviour depends on magnet geometry and the application.

Design Question

If additional space is available, should you increase:

  • magnet grade;
  • diameter;
  • thickness;
  • number of magnets;
  • steel thickness?

The best answer depends on what currently limits the magnetic system.

When a Larger Magnet Helps More Than a Higher Grade

A larger magnet may be the better solution when:

  • additional installation space is available;
  • more contact area is useful;
  • the target steel can support the larger magnetic circuit;
  • the existing magnet volume is simply too small;
  • a large working distance must be considered;
  • the application benefits from distributing the load across a larger area.

In these situations, increasing physical size may provide a larger practical improvement than moving from one grade to another.

Design Change Typical Effect
Increase magnet grade More magnetic capability within similar volume
Increase diameter / face area More working area and often greater total pull-force potential
Increase thickness Can increase field strength and available magnetic energy, up to diminishing returns
Reduce air gap Can produce a major practical improvement without changing the magnet
Increase steel thickness Can help the magnetic circuit use more of the magnet's potential

When a Higher Grade Makes Sense

A higher grade is particularly useful when the physical dimensions of the magnet cannot change.

Examples include:

  • a fixed cavity;
  • a thin product design;
  • a restricted diameter;
  • tight machine clearances;
  • existing tooling;
  • a standard product housing.

If geometry is fixed and the surrounding magnetic circuit is capable of supporting additional flux, moving to a higher grade can provide more performance without changing the physical size.

Best Practice

Use higher magnet grade when space is constrained and the steel, air gap, geometry, and magnetic circuit have already been evaluated.

Steel Thickness and Magnetic Saturation

A larger or higher-grade magnet can only perform as well as the surrounding magnetic circuit allows.

If the target steel is too thin, the steel may become the limiting factor.

If part of the steel path approaches magnetic saturation, additional magnet strength may produce diminishing returns.

This means neither larger size nor higher grade should be considered independently from the target steel.

Example

Increasing from N35 to N52 may produce less improvement than expected if the magnet is attached to very thin sheet steel.

Increasing the steel thickness may produce a greater system-level improvement.

For more information, see:

Air Gap and Working Distance

Air gap can completely change the comparison between magnet sizes and grades.

A gap may be created by:

  • paint;
  • powder coating;
  • adhesive;
  • rubber;
  • plastic;
  • vinyl;
  • protective film;
  • surface irregularities.

As working distance increases, the magnetic field available at the target decreases.

In some applications, changing magnet geometry can be more effective at the required working distance than simply selecting a higher grade of the original geometry.

Engineering Insight

Before increasing magnet size or grade, reduce unnecessary air gap whenever possible. Improving the magnetic interface can sometimes provide the largest performance gain.

See SSKC-012 — The Air Gap Effect.

Pull Force vs Shear Force

Neither magnet size nor grade should be selected from pull force alone when the application is vertical.

A magnet may have high direct pull force but still slide on steel if surface friction is low.

In a shear application, performance depends on:

  • magnetic attraction;
  • surface friction;
  • air gap;
  • steel thickness;
  • load direction;
  • vibration;
  • leverage.

A larger bare magnet is not automatically better than a smaller rubber-coated magnetic assembly if sliding resistance is the actual design requirement.

See SSKC-013 — Pull Force vs Shear Force: Why Magnets Slide Before They Pull Off.

Pot Magnets and Magnetic Assemblies

Pot magnets demonstrate why complete assembly design can matter more than magnet grade alone.

A steel cup redirects magnetic flux toward the working face.

This can increase useful holding force compared with an exposed magnet of similar magnetic material.

The performance depends on:

  • magnet dimensions;
  • magnet grade;
  • steel cup geometry;
  • steel thickness;
  • pole design;
  • working face area;
  • air gap.

In other words, the magnetic circuit can sometimes provide more practical benefit than simply specifying the highest available neodymium grade.

Cost vs Performance

Higher-grade neodymium magnets can cost more than lower grades.

Larger magnets also use more magnetic material and may increase shipping weight, assembly size, and manufacturing cost.

The best design therefore considers performance per total system cost.

Option Potential Advantage Potential Limitation
Higher grade More magnetic capability in the same space Higher material cost; circuit may limit benefit
Larger magnet More magnetic volume and potentially more contact area Requires more space and adds weight
Optimized steel / reduced gap Can unlock existing magnet performance May require assembly redesign

The most expensive magnet is not necessarily the best-performing system.

Space and Weight Constraints

Applications often impose physical constraints.

For example:

  • a sensor housing may allow only a small magnet;
  • a display may require a very thin assembly;
  • a moving component may need minimal weight;
  • a product may have a fixed mounting cavity;
  • a retrofit may need to fit an existing hole pattern.

In these situations, higher grade can be especially valuable because increasing physical dimensions may not be possible.

Conversely, if space is readily available, a larger lower-grade magnet may sometimes provide a more economical solution.

Real-World Applications

Industrial Fixtures

Larger magnetic contact areas can provide useful holding force and load distribution when space allows.

Machine Sensors

Compact housings may make higher-grade magnets attractive when dimensions cannot increase.

Signage

Increasing magnetic area can sometimes be more useful than selecting the highest grade, especially when loads are distributed over a panel.

Retail Displays

Space, appearance, steel thickness, and vertical shear performance may all influence the best design.

Vehicle Applications

Thin painted sheet metal and air gaps can limit the benefit of simply increasing magnet grade.

Automation

Compact magnetic assemblies may require careful optimization of grade, geometry, steel return paths, and operating distance.

Engineering Recommendations

Best Practice

  • Start with the required application performance, not the grade.
  • Determine the available installation space.
  • Evaluate magnet diameter, thickness, and volume separately.
  • Verify target steel thickness.
  • Reduce unnecessary air gaps.
  • Determine whether the load is pull, shear, or peeling.
  • Consider the complete magnetic circuit.
  • Compare total system cost, not magnet price alone.
  • Prototype using the actual finished assembly.
  • Apply an appropriate safety factor.

Expert Tip

If you have room to increase magnet size, compare that option against increasing grade. If size is fixed, grade becomes a more important design lever—but only after steel, air gap, and geometry have been checked.

Common Mistakes

Common Mistake Why It Matters
Assuming N52 is always best Geometry and magnetic circuit may matter more
Comparing grade without comparing size Magnetic volume and contact area may be different
Increasing size without checking steel Thin steel may limit the larger magnet
Ignoring air gap The interface may be wasting available magnetic performance
Selecting only by pull force Real application may be shear, peeling, or dynamic loading
Ignoring cost and packaging The strongest magnet may not be the best system solution

Frequently Asked Questions

Is N52 always stronger than N35?

For magnets with the same dimensions, shape, magnetization, and comparable conditions, N52 generally provides greater magnetic capability than N35. However, a larger N35 magnet can still provide more total holding force than a smaller N52 magnet.

Does magnet size matter more than grade?

Sometimes. Increasing magnet dimensions can increase magnetic volume, working area, and total holding potential. The better option depends on the application's geometry, steel, air gap, and available space.

Is a larger magnet always stronger?

A larger magnet often provides greater magnetic capability, but performance depends on geometry, magnetization, steel thickness, air gap, and the magnetic circuit. Size alone does not guarantee the best result.

Should I increase magnet diameter or thickness?

It depends on the application. Increasing diameter changes working-face area and field distribution, while increasing thickness changes magnetic volume and field characteristics. The most effective change depends on the current geometry and working distance.

Can a small N52 magnet outperform a larger N35 magnet?

It can in some comparisons, but not universally. The larger N35 magnet may contain much more magnetic material and have greater contact area. The complete geometry must be compared.

When should I use N52?

N52 can be useful when maximum magnetic performance is required within a tightly constrained volume and the surrounding magnetic circuit can support the additional flux.

Can higher grade compensate for an air gap?

It may help, but reducing unnecessary air gap can often be more effective. The working distance should be evaluated before simply increasing grade.

Can higher grade compensate for thin steel?

Not always. If the target steel is limiting or approaching magnetic saturation, increasing grade can produce diminishing returns.

What matters more for pull force: grade or contact area?

Both can matter. Pull force depends on the complete field distribution across the working area, the magnet geometry, target steel, air gap, and magnetic circuit. There is no universal rule that one always dominates.

What is the best way to compare two magnets?

Compare the complete specifications: dimensions, grade, magnetization, geometry, pull-force test conditions, working distance, target steel, temperature, and intended load direction.

Canadian Perspective

Canadian manufacturers often compare magnets sourced from different suppliers and regions where the same application may be quoted using different grades, dimensions, pull-force test methods, and steel conditions.

A quote for N52 is not automatically a technical upgrade over an N42 or N35 solution if the dimensions, geometry, steel thickness, coating, or testing method are different.

Canadian applications may also involve cold temperatures, moisture, road salt, painted steel, powder coating, and outdoor exposure.

For reliable supplier qualification, compare the complete magnetic assembly and test it under representative Canadian operating conditions.

Safety Reminder

Larger and higher-grade neodymium magnets can create substantial forces and may snap together unexpectedly.

They can cause pinch injuries, chip or fracture on impact, damage sensitive equipment, and create unexpected movement in assemblies.

Do not use nominal pull force as a safe working load. For critical applications, use appropriate engineering safety factors, representative testing, and secondary retention where required.

Conclusion

Magnet size and magnet grade are both important, but they affect performance in different ways.

A higher grade provides greater magnetic capability within a given volume.

A larger magnet can change:

  • magnetic volume;
  • working-face area;
  • field distribution;
  • total pull-force potential;
  • working-distance performance.

The best solution depends on the complete magnetic system:

  • magnet dimensions;
  • magnet grade;
  • geometry;
  • target steel;
  • air gap;
  • load direction;
  • available space;
  • cost;
  • environment.

A larger magnet is often more useful than a higher grade—but the right answer depends on the complete application.

Instead of asking only “What is the strongest grade?”, ask:

What combination of size, grade, geometry, steel, and working distance provides the best real-world performance?

Need Help Choosing Magnet Size and Grade?

The Simple Signman team helps Canadian manufacturers, designers, distributors, sign professionals, and industrial businesses evaluate permanent magnets and magnetic assemblies for real-world applications.

When requesting assistance, provide:

  • available magnet dimensions;
  • required holding force;
  • target steel thickness;
  • air gap or coatings;
  • mounting orientation;
  • available installation space;
  • operating temperature;
  • environmental conditions;
  • required quantities.

We can help compare size, grade, geometry, and magnetic circuit options—not simply specify the highest available grade.

Contact Simple Signman →

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Next: SSKC-017 — Magnet Shape and Aspect Ratio: Why Geometry Changes Magnetic Performance

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About Simple Signman

Since 1969, Simple Signman has been Canada's leading source for flexible magnetic materials and neodymium magnets. We help manufacturers, printers, distributors, sign professionals, and industrial businesses find magnetic solutions that perform reliably in real-world applications.

Sharing Magnetic Knowledge Since 1969.

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