When you compare magnets, a higher grade number does not automatically mean greater holding force. A practical magnet strength chart helps you understand how neodymium, ferrite, samarium cobalt, and alnico magnets differ in grade, field strength, temperature resistance, and typical use. You also need to look beyond labels such as N35 or N52. Magnet size, shape, air gap, steel target, coating, and operating temperature can change real-world performance. In this guide, you will learn how to read magnet grades, compare strength measurements, and choose the right magnet for your application.
What Does Magnet Strength Mean?
Magnet strength is made up of a few different measurements, and understanding each one will help you pick the right magnet.
Residual Induction (Br)
Residual induction, or Br, is how much magnetism stays in a magnet once it's fully magnetized. Think of it as the magnet's raw power level, measured in Gauss or Tesla. A higher Br usually means a stronger magnet, but it's not the full picture. Two magnets with the same Br can pull differently depending on their size and shape.
Pull Force or Holding Force
Pull force, or holding force, is the number you care about most: how much weight the magnet can lift or hold against a steel surface. Unlike Br, pull force isn't a fixed material property. It depends on the magnet's size and shape, the thickness of the steel it touches, and any gap between them. That's why two magnets with the same grade can have very different pull ratings once they're cut into different shapes.
Magnet Strength Chart by Material
The chart below compares the main permanent magnet materials by relative strength, temperature resistance, corrosion resistance, and common industrial applications.
| Magnet Material | Common Grade Naming | Relative Strength | Temperature Resistance | Corrosion Resistance | Typical Applications |
|
Neodymium |
N35–N52, with M, H, SH, UH, or EH suffixes | Very High | Medium to High | Medium | Motors, sensors, magnetic chucks, magnetic assemblies |
|
Samarium Cobalt |
SmCo 1:5 and 2:17 | High | Excellent | Excellent | Aerospace equipment, high-temperature motors, sensors |
|
Ferrite |
Ferrite material grades | Low to Medium | Good | Excellent | Magnetic separators, speakers, motors, industrial fixtures |
|
Alnico |
Alnico grades | Medium | Excellent | Good | Instruments, sensors, generators, high-temperature applications |
What Do N35, N42, N48, and N52 Mean?
When you read a neodymium magnet grade, the letter N generally refers to a standard-temperature grade, while the number indicates the material's approximate maximum energy product, or BHmax, in MGOe. A higher number usually means greater magnetic energy density, but it does not directly guarantee higher pull force in your finished assembly.
| Neodymium Grade | Typical BHmax Range | Approximate Energy Density | Relative Strength | Common Applications |
| N35 | 33–36 MGOe | 263–286 kJ/m³ | Standard | General industrial magnets, sensors, fixtures |
| N42 | 40–43 MGOe | 318–342 kJ/m³ | High | Motors, magnetic bases, automation equipment |
| N48 | 46–49 MGOe | 366–390 kJ/m³ | Very High | Compact motors, sensors, magnetic assemblies |
| N52 | 50–53 MGOe | 398–422 kJ/m³ | Extremely High | High-performance motors and space-limited designs |
N35 vs N42 vs N52: Which Magnet Is Stronger?
| Grade | Relative Magnetic Strength | Main Advantage | Best Choice When You Need | Cost Consideration |
| N35 | Standard | Reliable performance and lower cost | A general-purpose magnet with enough installation space | Most economical |
| N42 | High | Good balance between strength and price | Stronger performance without the highest material cost | Moderate |
| N52 | Highest among these grades | Maximum energy density in a compact size | High magnetic force where space is limited | Most expensive |
How to Choose the Right Magnet Strength
Choosing magnet strength starts with your application, not the highest grade number. Follow these steps to balance performance and cost.
Define the Application
Explain how you will use the magnet, including load direction, movement, cycle frequency, space, and environment. A separator, motor, or fixture may need different performance.
Confirm Required Holding Force
Calculate the working load, including vibration, shock, shear, and safety factors. Catalog pull force applies only to defined steel, contact, and air-gap conditions.
Select the Magnet Material
Choose neodymium for compact strength, ferrite for economical corrosion resistance, samarium cobalt for high temperatures, or bonded magnets for complex shapes.
Select the Grade and Dimensions
Specify grade, dimensions, tolerance, coating, pole orientation, and magnetization direction. Geometry can affect force as much as grade.
Test Samples Before Bulk Production
Test samples under your actual load, air gap, temperature, and steel conditions. Confirm force, fit, durability, and safety before approving production.
Why Choose GME Magnet as a Supplier?
By now, you've seen how much grade, material, and dimensions affect whether a magnet actually works, and getting any of it wrong is expensive to fix later. That's where working with an experienced manufacturer matters. GME has 15+ years of experience producing neodymium, samarium cobalt, alnico, and flexible magnets to exact grade and dimension specs, certified to ISO 9001, ISO 14001, CE, and RoHS. If you're still unsure which grade or type fits your project, send us your requirements, and our team can help you work it out before you place an order, not after.
Neodymium Magnets
Samarium Cobalt Magnets
Alnico Magnets
Conclusion
Choosing the right magnet is easier when you follow a clear process. Start with your application, required holding force, working temperature, and available space. Then compare material types, select the appropriate grade and dimensions, and consider coating, magnetization direction, and air gap. Finally, test samples under your real operating conditions before placing a bulk order. This approach helps you balance magnetic performance, cost, and service life. If you need help comparing magnet grades or specifying a custom solution, send GME your drawing, application details, and quantity. Our team can review your requirements and recommend a suitable magnet option for your project.
FAQ
Q: What is the strongest type of permanent magnet?
A: Neodymium (NdFeB) is the strongest permanent magnet material available today. Samarium cobalt comes next, especially in high-heat settings, followed by alnico and ferrite.
Q: Is N52 stronger than N35?
A: Yes. At the same size, N52 is roughly 30–40% stronger than N35. The number after the N reflects the magnet's maximum energy product, so a higher number means a stronger magnet.
Q: Does a higher magnet grade always mean higher pull force?
A: Not necessarily. Grade tells you strength at a given size, but pull force also depends on shape, thickness, and what the magnet is holding onto. A smaller high-grade magnet can still pull less than a larger low-grade one.
Q: Which magnet is best for high-temperature applications?
A: Alnico and samarium cobalt handle heat best, with alnico tolerating the highest temperatures of any common type. Standard neodymium weakens as it heats up, though high-temperature grades like N42SH hold up much better.
Q: Are ferrite magnets cheaper than neodymium magnets?
A: Yes, ferrite (ceramic) magnets cost significantly less than neodymium, which is why they're common in large-volume or budget-sensitive applications. The trade-off is that ferrite is much weaker for its size.
Q: How is magnet pull force measured?
A: Pull force is tested by measuring how much straight-line force it takes to pull a magnet off a flat steel plate of a set thickness. It's usually given in pounds or kilograms, and results can shift depending on the exact test setup.
