What do M, H, SH, UH, EH and AH mean on a neodymium grade?

They are intrinsic coercivity classes that set the maximum operating temperature: M up to 100C, H up to 120C, SH up to 150C, UH up to 180C, EH up to 200C, AH up to 230C. No letter means standard, up to 80C.

Technical Reference · Manufacturer Datasheet

NdFeB Magnet Grades: Full Specs & Selector

Q: What is the strongest neodymium magnet grade?

N52 is the strongest grade in routine commercial production, at about 50 to 53 MGOe. N55 exists but is specialised and limited. Strength and heat resistance are separate: N52 is strongest at room temperature but has the lowest heat tolerance, up to 80 degrees C.

Q: What is the difference between N35, N42 and N52?

Only the energy product, which is strength. N52 is about 48 percent stronger than N35, producing the same field in a smaller, lighter magnet. All three share the same 80C ceiling, so for warm environments you need a suffix grade such as N42SH rather than just a higher number.

Q: Can N52 be used at high temperature?

No. Standard N52 starts to lose magnetism irreversibly above about 80 degrees C. For heat you trade some strength for a higher coercivity class. There is no N52UH because the chemistry needed for high coercivity caps the achievable energy product.

Q: Do you have a minimum order, and can you customise a grade?

There is no MOQ on custom orders, so a grade can be qualified on prototypes before scaling. Chemistry, coating, magnetization direction and tolerance can all be tailored to a drawing.

Every sintered neodymium grade from N30 to N52, across all seven temperature classes — with live Br, Hcj, BHmax data, a grade selector, and side-by-side comparison. Built by a magnet maker, for the engineers and buyers who spec them.

51Grades listed

7Temp classes

35–52MGOe range

1992Maker since

Start Here

How to read an NdFeB grade

A sintered neodymium grade is three pieces of information packed into one code. Read all three before you order — the number sets strength, the suffix sets heat resistance, and getting either wrong is the most common cause of a magnet failing in the field. New to this? Read the full neodymium magnet grades explainer first.

N42SH

N — Neodymium

Marks it as a sintered NdFeB (neodymium-iron-boron) magnet. Constant across every grade.

N42SH

42 — Energy Product

The maximum energy product (BHmax) in MGOe. Higher = stronger field from less magnet. Ranges 30–52.

N42SH

SH — Temp Class

The intrinsic coercivity class — how much heat the magnet tolerates. Blank, M, H, SH, UH, EH, or AH.

Tool 01 · Live Data

Full sintered NdFeB grade chart

Filter by temperature class, search a grade, or click any column header to sort. All values measured at 20°C; magnets are made to order, so these are the standard reference ranges we build to.

☷

NdFeB Grade Specifications

Grade ▲▼	Br (mT) ▲▼	Hcb (kOe) ▲▼	Hcj (kOe) ▲▼	(BH)max (MGOe) ▲▼	Max Temp (°C) ▲▼	Class ▲▼

Br remanence · Hcb normal coercivity · Hcj intrinsic coercivity (the heat-resistance number) · (BH)max energy product. Temperature coefficients: α(Br) −0.09 to −0.12 %/°C, β(Hcj) −0.40 to −0.60 %/°C. Need N55 or a custom spec? Ask us.

Temperature Classes

What the suffix really protects you from

The letter after the number is an intrinsic-coercivity (Hcj) class. The higher the class, the higher the safe operating temperature — but only up to the grade's knee point, and the more heavy rare earth (Dy/Tb) it needs.

≤ 80°C

Standard. Max strength at room temperature. Electronics, sensors, holding, separators.

≤ 100°C

Medium. A small heat buffer over standard for warm enclosures.

≤ 120°C

High. General motors and actuators that warm up in use.

≤ 150°C

Super High. Servo & BLDC motors, pumps, automotive accessories.

≤ 180°C

Ultra High. EV traction, robotics joint actuators, generators.

≤ 200°C

Extra High. Demanding automotive and industrial drive motors.

≤ 230°C

Abnormal High. Downhole, aerospace, severe-duty heat. (Or step to SmCo.)

Rule

+ margin

Always leave 20–30°C headroom over your worst-case temperature, and account for magnet shape.

Tool 02 · Interactive

Find my grade

Answer two quick questions and we'll point you to a starting grade. It's a guide, not a final spec — magnet geometry and your demag curve matter too, which is exactly what our engineers verify on a real quote.

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Grade Selector

Tool 03 · Compare

Compare grades side by side

Pick up to three grades to see remanence, energy product, and temperature ceiling next to each other. Great for settling the classic “is N45SH really worth it over N42SH?” question.

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Grade Comparison

Grade A

Grade B

Grade C

Tool 04 · Handy

Magnetic unit converter

Datasheets mix CGS and SI. Convert the three units that trip everyone up — type in any field and the rest update.

⇄

CGS ↔ SI Converter

Flux Density (Br)

Gauss

Tesla

Field Strength (H)

kOe

kA/m

Energy Product (BH)max

MGOe

kJ/m³

1 T = 10,000 Gauss · 1 kOe = 79.577 kA/m · 1 MGOe = 7.9577 kJ/m³

By Application

Which grade for which job

A practical starting point by use case. Operating temperature is usually the first filter, then strength vs. cost. Click through to the matching product or application page.

Application	Typical grades	Why
Consumer electronics, sensors, closures	N35 – N42	Room temperature; cost and strength balance. Disc / block.
Holding, separators, fixtures	N42 – N52	Max pull at ambient temperature. Often N52 for compact holders.
Speakers & audio	N42 – N45	High flux in tight magnetic gaps; moderate heat.
Servo & BLDC motors	N42SH – N45SH	Heat from windings; needs SH coercivity. Arc magnets.
EV traction motors	N42UH, N35EH	High peak load & heat; UH/EH resist demag. EV motor magnets.
Industrial motors & generators	N45SH, N48H	Continuous duty, sustained heat. Industrial motors.
Robotics & humanoid joints	N45UH, N48UH	Torque density in hot, sealed actuators; GBD-made. Humanoid robots.
Drone & RC motors	N48H – N52	Max torque-to-weight; shorter thermal duty. Robotics range.
MRI & scientific instruments	N48 – N52	Highest field where temperature is controlled.
Downhole, aerospace, severe heat	N35AH or SmCo	Beyond 200°C; AH grade or switch to samarium cobalt. Custom solutions.

Buyer relevanceThese are starting points, not guarantees. Real grade choice depends on your magnet's shape (its permeance coefficient), peak current, and worst-case ambient. Send the drawing and operating conditions and we'll confirm the grade on the actual demag curve.

N35 vs N42 vs N52 — what actually changes

The three most-searched grades. The jump from N35 to N52 is about a 48% increase in energy product — meaning a smaller, lighter magnet for the same field — but all three share the same standard 80°C temperature ceiling.

Grade	Br (mT)	(BH)max	Max Temp	Best for
N35	1170–1220	33–36 MGOe	≤80°C	Cost-sensitive, general purpose
N42	1280–1330	40–43 MGOe	≤80°C	The all-round default
N52	1420–1480	50–53 MGOe	≤80°C	Maximum strength in minimum space

Buyer relevanceHigher grade is not “better” — it's stronger but more brittle and pricier, and none of these three tolerate heat. If your part runs warm, an N42SH beats an N52 every time. Compare them in the comparison tool above.

Why Source From Mainrich

Grades backed by a real factory

A grade on a datasheet only matters if the magnet actually meets it. We've made sintered NdFeB since 1992, and every grade above is something we melt, press, sinter, and test in-house.

In-house process

Melt to finish, under one roof

Strip casting, jet milling, field pressing, sintering and tempering — not traded from a third party.

High-temp grades

GBD for UH/EH/AH

We use grain boundary diffusion to hit high coercivity with less scarce, export-controlled Dy/Tb.

Verified, not assumed

Demag curve & flux QC

Each batch is checked for Br, Hcj, and dimensions, with demag curves available on request.

Full coating range

Ni-Cu-Ni to parylene

Salt-spray and pressure-cooker rated finishes matched to your environment — zinc, epoxy, Teflon, gold, parylene and more.

No minimum

Prototype to production

No MOQ on custom orders — qualify a grade on a handful of parts before scaling.

Compliance ready

Export & RoHS support

Documentation for Dy/Tb content and 2025 export controls, plus RoHS / REACH declarations.

FAQ

NdFeB grade questions, answered

What does the “N” and the number in N52 mean?

The N stands for neodymium (sintered NdFeB). The number is the maximum energy product in MGOe — a measure of magnetic strength. N52 has roughly 52 MGOe, N35 has 35. The higher the number, the stronger the field from the same volume.

What is the strongest neodymium magnet grade?

N52 is the strongest grade in routine commercial production (about 50–53 MGOe). N55 exists but is specialised and limited. Remember strength and heat resistance are separate: N52 is the strongest at room temperature but has the lowest heat tolerance (≤80°C).

What do M, H, SH, UH, EH and AH mean?

They are intrinsic coercivity classes that set the maximum operating temperature: M ≤100°C, H ≤120°C, SH ≤150°C, UH ≤180°C, EH ≤200°C, AH ≤230°C. No letter means standard, ≤80°C.

What is the difference between N35, N42 and N52?

Only the energy product (strength). N52 is about 48% stronger than N35, so it produces the same field in a smaller, lighter magnet. All three share the same 80°C ceiling. For warm environments you need a suffix grade (e.g. N42SH), not just a higher number.

What grade is best for electric motors?

It depends on heat. Many servo and BLDC motors use N42SH or N45SH; EV traction motors lean to N42UH or N35EH; high-temp or downhole drives may need AH grades or samarium cobalt. Use the grade selector above as a starting point, then send us the operating conditions.

Can N52 be used at high temperature?

No — standard N52 starts to lose magnetism irreversibly above about 80°C. For heat you trade some strength for a higher coercivity class. There is no N52UH, because the chemistry needed for high coercivity caps the achievable energy product.

Why do high-temperature grades cost more?

They contain more heavy rare earth (dysprosium and terbium) to raise coercivity, and those elements are scarce, costly, and export-controlled. We use grain boundary diffusion to minimise the Dy/Tb needed for a given temperature class.

Do you have a minimum order, and can you customise a grade?

No MOQ on custom orders — you can qualify a grade on prototypes before scaling. We also tailor chemistry, coating, magnetization direction and tolerance to your drawing. Send your spec for a quote.

Keep Exploring

Related resources

Guide

Grades Explained

The plain-language walkthrough of what grades mean and how to choose one.

Reference

Magnet Glossary

110+ terms — BHmax, coercivity, knee point, GBD — defined for buyers.

Products

Custom Neodymium Magnets

Any grade above, made to your drawing with coating and magnetization to spec.

Application

EV Motor Magnets

UH and EH grades for traction motors that run hot under peak load.

Compliance

Export Compliance 2026

What to verify on Dy/Tb content before ordering high-temp grades.

Support

FAQ

Sourcing, lead times, tolerances, shipping, and documentation.

Got a grade in mind? Let's spec it properly.

Send your drawing or operating conditions — temperature, field target, environment — and our engineers confirm the grade, coating, and magnetization, backed by demag curves and dimensional reports.

Get a Quote → Sintered NdFeB maker since 1992 · No MOQ on custom orders · ISO 9001 & IATF 16949