A magnet grade describes a range of magnetic material properties; it does not directly tell you the pull force or surface gauss of a finished magnet. For neodymium (NdFeB) magnets, grades such as N35, N42 and N52 primarily indicate the material’s maximum energy product (BHmax), while suffixes such as M, H, SH, UH and EH indicate higher intrinsic coercivity classes used for increased resistance to irreversible demagnetization at elevated temperature.

The right grade is therefore not simply “the highest number available.” Engineers should select the lowest-cost grade that reliably meets the required field, force, temperature, demagnetization margin, geometry and environmental conditions.

What Does a Magnet Grade Mean?

For sintered neodymium magnets, the grade designation combines two ideas:

The number—such as 35, 42 or 52—corresponds approximately to the material’s maximum energy product, BHmax, in MGOe.
The suffix—such as H, SH or UH—indicates a higher intrinsic coercivity class, which generally provides more resistance to irreversible demagnetization at elevated temperature or under opposing magnetic fields.

For example, N42 and N42SH can have similar room-temperature energy density, but N42SH has substantially higher intrinsic coercivity and is designed for more demanding thermal conditions.

N35 vs. N42 vs. N52: What Changes?

Typical NdFeB grade	Approx. BHmax range	Relative energy density	Typical reason to choose it
N35	About 33–36 MGOe	Standard	Cost-effective general-purpose designs
N42	About 40–43 MGOe	Higher	Good balance of strength, availability and cost
N48	About 46–49 MGOe	High	Compact designs needing more energy density
N52	About 49–53 MGOe	Very high	Maximum room-temperature energy density in a compact package

Important: moving from N42 to N52 does not mean a finished magnet automatically gains 24% more pull force or surface gauss. The grade number tracks BHmax, while actual device performance also depends on magnet dimensions, aspect ratio, air gap, steel circuit, magnetization direction and operating point.

What Is BHmax?

BHmax, or maximum energy product, is a measure of the magnetic energy density available from the material. It is useful for comparing how much magnetic performance can be obtained from a given magnet volume in a well-designed magnetic circuit.

BHmax is not the same as:

Surface gauss
Pull force
Remanence (Br)
Intrinsic coercivity (HcJ)

When comparing U.S./CGS and SI datasheets, use our Magnetic Unit Converter for MGOe ↔ kJ/m³, Gauss ↔ Tesla and Oersted ↔ kA/m conversions.

Br, HcB and HcJ: The Other Numbers That Matter

Property	What it means	Why engineers care
Br — Remanence	Residual flux density of the magnetic material after magnetization	Relates to available magnetic flux
HcB — Normal coercivity	Reverse field required to reduce B to zero	Defines part of the normal demagnetization curve
HcJ — Intrinsic coercivity	Reverse field required to reduce intrinsic magnetization to zero	Critical for resistance to irreversible demagnetization
BHmax	Maximum energy product	Primary basis of the NdFeB grade number

For a line-by-line explanation of these values, see How to Read a Magnet Datasheet: Br, HcJ & BHmax Explained.

What Do M, H, SH, UH, EH and AH Mean?

Neodymium grade suffixes indicate higher coercivity classes. The exact limits depend on the manufacturer and grade family, but the table below shows common industry conventions.

Suffix	Typical minimum HcJ	Common published max operating temperature*
No suffix	About ≥12 kOe	About 80 °C
M	About ≥14 kOe	About 100 °C
H	About ≥17 kOe	About 120 °C
SH	About ≥20 kOe	About 150 °C
UH	About ≥25 kOe	About 180 °C
EH	About ≥30 kOe	About 200 °C
AH	About ≥33–35 kOe	Up to roughly 220–230 °C in suitable designs

*These are common published guidelines, not universal guarantees. Actual safe operating temperature depends on grade, magnet geometry, permeance coefficient, magnetic circuit and opposing field.

Why Temperature Suffixes Matter

NdFeB loses some magnetic output reversibly as temperature rises, but the larger engineering concern is irreversible demagnetization. Intrinsic coercivity falls with increasing temperature, and a magnet with insufficient HcJ can cross the knee of its demagnetization curve.

This is especially important in:

Electric motors and generators
Automotive under-hood systems
Sensors near heat-generating electronics
Industrial actuators
Medical equipment exposed to elevated temperature
Thin magnets or low-permeance geometries

Use our Magnet Temperature Derating Calculator and Magnet Demagnetization Calculator when temperature and operating-point margin are important.

Is N52 Always Stronger Than N42?

As a material, N52 generally has higher Br and BHmax than N42. As a finished component, however, “stronger” depends on the geometry and application.

A larger N42 magnet may easily produce more pull force than a smaller N52 magnet. Likewise, an N42SH magnet may outperform a standard N52 in a hot motor if the N52 suffers irreversible demagnetization.

That is why engineers should compare the complete magnetic circuit rather than selecting a grade from the number alone.

Does a Higher Grade Mean More Surface Gauss?

Usually a higher-Br grade can produce more field in the same geometry, but there is no fixed surface-gauss value for a grade. Surface field depends heavily on dimensions, aspect ratio, measurement position and nearby ferromagnetic material.

For example, two N52 magnets with different thickness-to-diameter ratios can have very different surface-gauss readings even though the material grade is identical.

See What Is Gauss? How Gauss Measurement Works for the correct way to interpret a gauss reading.

Does a Higher Grade Mean More Pull Force?

Not by a fixed percentage. Pull force depends on:

Magnet dimensions and contact area
Material grade
Air gap
Steel target thickness and composition
Surface condition
Magnetic circuit geometry

Use the Magnet Pull Force Calculator when the functional requirement is mechanical holding force rather than material energy density.

Is N52 More Brittle Than N35?

Not in a way that should drive grade selection. Sintered NdFeB magnets are hard and brittle across the grade family. Differences in grade are primarily magnetic-property differences, not a simple progression where higher grade numbers become progressively more brittle.

Finished NdFeB magnets should generally be protected from impact and should not be drilled, cut or conventionally machined after magnetization. See Why Finished Magnets Should Not Be Cut or Ground.

How to Choose the Right Neodymium Grade

If your main requirement is…	What to evaluate first
Lowest practical cost	N35–N42 range if it meets field/force requirements
Maximum magnetic output in minimum space	Higher-energy grades such as N48 or N52
Elevated operating temperature	Higher-coercivity M, H, SH, UH, EH or AH families
Strong opposing magnetic field	HcJ and demagnetization margin
Very thin geometry	Permeance coefficient and higher coercivity
High-volume production	Lowest grade that reliably meets the specification

Grade Selection for Common Applications

Electric Motors

Motor magnets should be selected using both magnetic energy and coercivity. Rotor temperature, armature reaction, air gap and geometry can make a high-coercivity grade more important than the highest possible Br. See How Magnets Work in Electric Motors.

Sensors

For Hall, reed and magnetoresistive sensors, specify the required field at the actual sensor distance and orientation. A grade alone does not define the functional field.

Holding Magnets

For room-temperature holding applications with a favorable steel circuit, a lower-cost grade may provide the required force without the cost of N52.

Medical and Electronics Applications

Compact electronics and medical devices may favor higher-energy grades for size reduction, but temperature, coating, dimensional tolerances and compliance requirements can be equally important.

What About SmCo, Ferrite and Alnico Grades?

Grade naming systems differ between magnet material families, so an NdFeB-style grade number should not be applied universally.

Samarium cobalt (SmCo) grades are commonly identified by alloy family and energy-product range, with strong emphasis on temperature stability and coercivity.
Ferrite / ceramic grades use their own classification systems and offer much lower energy density than NdFeB but excellent corrosion resistance and low cost.
Alnico grades are selected around composition, magnetic properties, heat treatment and magnetic-circuit requirements.

Use our Magnet Material Comparison for a side-by-side engineering comparison of NdFeB, SmCo, ferrite and Alnico.

What Procurement Teams Should Put on the Drawing or RFQ

Do not specify only “N42 magnet” if the application has meaningful thermal or magnetic risk. A production specification should normally define:

Material family and grade
Dimensions and tolerances
Magnetization direction
Coating or finish
Continuous and maximum excursion temperature
Required HcJ, Br or other magnetic-property limits when critical
Functional field, force or torque requirement
Magnetic inspection method and test location
Annual volume
Traceability, PPAP, COC or compliance-document requirements

For engineered sourcing, use the Magnet RFQ Builder. If the dimensions and grade are already known, search Radial Magnets inventory.

Frequently Asked Questions

What does N52 mean in a magnet?

N52 is a sintered NdFeB material grade whose maximum energy product is typically in the approximate 49–53 MGOe range. It is one of the highest-energy commonly available neodymium grades.

Is N52 stronger than N35?

As a material, N52 has higher energy density and generally higher Br than N35. But finished-magnet force still depends on the magnet’s dimensions, geometry, air gap and magnetic circuit.

What does N42SH mean?

N42 identifies the approximate energy-product class, while SH identifies a higher intrinsic-coercivity class intended for more demanding temperature and demagnetization conditions than a standard N42 grade.

What is the strongest neodymium magnet grade?

N52 is one of the highest-energy grades widely used commercially, although specialty grades and manufacturer-specific offerings can vary. The highest BHmax is not always the best engineering choice if temperature or coercivity is the limiting factor.

Which magnet grade is best for high temperature?

There is no single best grade. Higher-coercivity families such as SH, UH and EH are commonly evaluated for elevated temperature, but the correct grade depends on geometry, magnetic circuit, opposing field and maximum temperature.

Does magnet grade determine pull force?

No. Grade affects the material properties available to the design, but pull force also depends strongly on magnet size, shape, air gap and the steel circuit.