Name: Magnet grade specifications: neodymium N35 to N55, M, H, SH, UH and EH grades, SmCo30 and ceramic
Creator: Apex Magnets

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What the N number means

The number in a neodymium grade is the material's maximum energy product, (BH)max, in MGOe: a higher number means a stronger magnet of the same size and shape.

N52 has an energy product of 49–53 MGOe against 33–36 MGOe for N35, so the same 1/2 × 1/8 inch disc pulls 6.62 lb in N52 and 4.49 lb in N35, about 47% more. Check any size and grade with our Magnet Pull Force Calculator.

Letters after the number mark high-temperature grades. M, H, SH, UH and EH grades have higher intrinsic coercivity (HcJ), so they keep their strength at higher temperatures: from 100 °C for M up to 200 °C for EH.

Apex Magnets stocks mostly N48, a good balance of strength and price. Other neodymium grades, including every high-temperature grade, are available by custom order. SmCo30 samarium cobalt and C-8 and C-11 ceramic magnets are stocked.

Standard N grades: N35 to N55

80 °C maximum working temperature, Curie temperature 320 °C.

Grade	Br		HcJ (min.)		HcB (min.)		(BH)max		Curie temp.	Max working temp.
Grade	T	kGs	kA/m	kOe	kA/m	kOe	kJ/m³	MGOe	°C	°C
N35	1.17–1.22	11.7–12.2	955	12	868	10.9	263–287	33–36	320	80
N38	1.22–1.26	12.2–12.6	955	12	899	11.3	287–310	36–39	320	80
N40	1.25–1.29	12.5–12.9	955	12	923	11.6	302–326	38–41	320	80
N42	1.28–1.32	12.8–13.2	955	12	923	11.6	318–342	40–43	320	80
N45	1.32–1.37	13.2–13.7	955	12	876	11	342–366	43–46	320	80
N48 Stocked	1.37–1.42	13.7–14.2	955	12	892	11.2	366–390	46–49	320	80
N50	1.39–1.44	13.9–14.4	955	12	836	10.5	374–406	47–51	320	80
N52	1.42–1.47	14.2–14.7	876	11	836	10.5	390–422	49–53	320	80
N55	1.46–1.52	14.6–15.2	876	11	716	9	414–446	52–56	320	80

High-temperature grades: M, H, SH, UH and EH

Representative grades from each series. Every grade in a series's range is available by custom order.

Grade	Br		HcJ (min.)		HcB (min.)		(BH)max		Curie temp.	Max working temp.
Grade	T	kGs	kA/m	kOe	kA/m	kOe	kJ/m³	MGOe	°C	°C
M grades: 100 °C maximum working temperature, Curie temperature 330 °C. Range N30M to N52M.
N35M	1.17–1.22	11.7–12.2	1,114	14	868	10.9	263–287	33–36	330	100
N42M	1.28–1.32	12.8–13.2	1,114	14	955	12	318–342	40–43	330	100
N52M	1.42–1.47	14.2–14.7	1,035	13	995	12.5	390–422	49–53	330	100
H grades: 120 °C maximum working temperature, Curie temperature 340 °C. Range N28H to N50H.
N35H	1.17–1.22	11.7–12.2	1,353	17	868	10.9	263–287	33–36	340	120
N42H	1.28–1.32	12.8–13.2	1,353	17	955	12	318–342	40–43	340	120
N45H	1.32–1.37	13.2–13.7	1,353	17	971	12.2	342–366	43–46	340	120
N50H	1.39–1.44	13.9–14.4	1,274	16	1,035	13	374–406	47–51	340	120
SH grades: 150 °C maximum working temperature, Curie temperature 350 °C. Range N28SH to N48SH.
N35SH	1.17–1.22	11.7–12.2	1,592	20	876	11	263–287	33–36	350	150
N42SH	1.28–1.32	12.8–13.2	1,592	20	971	12.2	318–342	40–43	350	150
N48SH	1.37–1.42	13.7–14.2	1,512	19	995	12.5	358–390	45–49	350	150
UH grades: 180 °C maximum working temperature, Curie temperature 360 °C. Range N28UH to N42UH.
N35UH	1.17–1.22	11.7–12.2	1,990	25	860	10.8	263–287	33–36	360	180
N42UH	1.27–1.32	12.7–13.2	1,990	25	971	12.2	310–342	39–43	360	180
EH grades: 200 °C maximum working temperature, Curie temperature 370 °C. Range N28EH to N38EH.
N35EH	1.17–1.22	11.7–12.2	2,388	30	836	10.5	263–287	33–36	370	200
N38EH	1.20–1.26	12.0–12.6	2,388	30	915	11.5	279–310	35–39	370	200

Samarium cobalt and ceramic

Samarium cobalt (Sm2Co17) and ceramic (ferrite). All three grades are stocked.

Grade	Br		HcJ		HcB		(BH)max		Curie temp.	Max working temp.
Grade	T	kGs	kA/m	kOe	kA/m	kOe	kJ/m³	MGOe	°C	°C
SmCo30	1.08–1.10	10.8–11.0	1,432	18	788	9.9	223–239	28–30	820	300
C-8	≥ 0.385	≥ 3.85	243	3.05	235	2.95	≥ 27.8	≥ 3.50	460	250*
C-11	≥ 0.430	≥ 4.30	204	2.56	200	2.51	≥ 34.4	≥ 4.32	460	250*

SmCo30 Br and (BH)max are minimum–typical values; ceramic values are minimums (≥). *Ceramic maximum working temperature is Apex Magnets' product rating (482 °F).

HcJ and HcB are minimum values; Br and (BH)max are min–max ranges for neodymium. Figures come from our supplier's grade datasheet and are subject to manufacturer tolerance. Convert kGs ↔ T, kOe ↔ kA/m and MGOe ↔ kJ/m³ with our Magnetic Unit Converter.

Br is not surface gauss. Br is a property of the magnet material, measured in a closed magnetic circuit. The “Gauss (Surface)” value on each product page is the field measured at the magnet's face in open air, so it depends on the magnet's size and shape and is always much lower. For example, our 1/2 × 1/8 inch N48 disc has a Br of 13,700–14,200 gauss but a surface field of 3,402 gauss.

Choosing a grade by temperature

Choose the first series whose maximum working temperature is above the hottest temperature the magnet will reach; each step up in heat resistance lowers the strongest grade available.

Series	Max working temperature	Curie temperature	Strongest grade
N (standard)	80 °C / 176 °F	320 °C	N55 (52–56 MGOe)
M	100 °C / 212 °F	330 °C	N52M (49–53 MGOe)
H	120 °C / 248 °F	340 °C	N50H (47–51 MGOe)
SH	150 °C / 302 °F	350 °C	N48SH (45–49 MGOe)
UH	180 °C / 356 °F	360 °C	N42UH (39–43 MGOe)
EH	200 °C / 392 °F	370 °C	N38EH (35–39 MGOe)
Samarium cobalt	300 °C / 572 °F	820 °C	SmCo30 (28–30 MGOe)

Above 200 °C, the options are AH neodymium grades, rated to 220 °C (428 °F) and made up to N33AH, or SmCo30 samarium cobalt, rated to 300 °C (572 °F), which we stock.

These ratings assume a typical magnet shape. Thin magnets, and magnets working against a strong opposing field, lose strength at lower temperatures, so allow a margin. Below its rated temperature, a warm magnet is slightly weaker but recovers fully as it cools; above it, part of the loss is permanent. More in our FAQ: What temperature do neodymium magnets lose strength?

What the specifications mean

Br (remanence)The residual flux density of the material, in tesla (T) or kilogauss (kGs). It describes the material in a closed circuit, not the field at a finished magnet's surface.
HcJ (intrinsic coercivity)The reverse field, in kA/m or kOe, needed to fully demagnetize the material. Higher HcJ means better resistance to heat and opposing fields; it is what the M to EH grades increase.
HcB (normal coercivity)The reverse field needed to bring the magnet's flux density to zero. It is always lower than or equal to HcJ.
(BH)max (maximum energy product)The material's maximum stored magnetic energy, in kJ/m³ or MGOe. It is the number in the grade name and the best single measure of strength.
Curie temperatureThe temperature at which the material loses its magnetism completely.
Max working temperatureThe highest temperature for normal use without a permanent loss of strength, for a typical magnet shape.