N35 vs N52: What Those Numbers on a Neodymium Magnet Actually Mean
If you've ever spec'd a neodymium magnet, you've run into the alphabet and number soup: N35, N42, N48, N52, sometimes with letters tacked on the end like N42SH. It's tempting to treat the number as a simple strength dial and just turn it up. Bigger number, stronger magnet, done. That instinct isn't wrong, exactly. It's just missing the part of the story that actually determines whether the magnet survives in your application. For a complete background on who I am and why this post exists, head over to the Introduction to Alisa Learns about Magnets.
💡 TLDR: What we're covering
De-Coding the N-Scale: What (BH)max and Remanence (Br) actually mean, and why N52 delivers roughly 50% more holding force than N35 at the same size.
The Price of Peak Performance: The raw cost-to-strength trade-offs and where the point of diminishing returns begins.
The High-Temperature Blind Spot: Why a stronger magnet is often less stable in heat, and how to read suffix grades (M, H, SH, UH, EH) to find your actual thermal ceiling.
Application Matchmaking: A quick breakdown of when N35 is the smarter, cost-sensitive choice—and when N52 actually justifies its premium.
What the "N" and the number mean
The N stands for neodymium, as opposed to SmCo, ceramic, or Alnico grades, which use their own naming conventions. The number that follows is the magnet's maximum energy product, or (BH)max, measured in Mega Gauss Oersteds (MGOe). That's the same figure we talked about in our B-H curve explainer, the most efficient point on the magnet's demagnetization curve. An N35 magnet has a (BH)max around 33 to 35 MGOe. An N52 sits near 50 to 52 MGOe. As of today, N52 is roughly the strongest grade commercially produced at scale. Going higher runs into diminishing returns and steep cost increases for very little practical gain.
Higher (BH)max generally tracks with higher remanence (Br) too. A typical N35 has a Br around 1.2 Tesla, while N52 runs closer to 1.4 Tesla. In real terms, that translates to meaningfully more pull force for the same size of magnet. Testing on standardized steel contact shows N52 delivering roughly 50% more holding force than N35 at equivalent dimensions.
The trade-off nobody puts on the label
Here's the part that trips people up. Going from N35 to N52 does not automatically buy you a better magnet. It buys you a stronger magnet, at room temperature, for more money. Standard grades run 30 to 60% higher in cost as you move toward N52, driven by rare earth content and tighter manufacturing tolerances. What it doesn't automatically buy you is better heat resistance. The base "N" grades generally fall under a standard maximum operating temperature of up to 80°C. However, it's worth noting that because N52 pushes the extreme limits of magnetic energy, its actual real-world temperature ceiling often drops closer to 60°C or 65°C. A stronger magnet isn't a hotter rated magnet; at the extreme top end, it’s often the opposite.
That's what the letter suffixes are for. M, H, SH, UH, and EH grades trade away some peak (BH)max in exchange for higher intrinsic coercivity (Hci) and a higher rated operating temperature, sometimes well past 150°C or even 200°C for EH grades. If your application runs hot, the right move usually isn't "go bigger." It's "go to a temperature stable grade," even if that means a lower headline number.
So which one do you actually want?
For general holding, mounting, and cost sensitive designs such as separation equipment, fixtures, and low heat consumer parts, N35 is often the smarter choice, not the cheaper compromise. You're not paying for strength you can't use.
For applications where every cubic millimeter counts and you need maximum force from the smallest possible footprint, think precision motors, robotics, compact sensor assemblies, and some medical devices, N52 earns its premium, provided the operating environment stays within its temperature limits.
And for anything that runs hot, like motor windings, under hood automotive, or industrial equipment near a heat source, the conversation shouldn't start with the N number at all. It should start with the operating temperature and Hci, then work backward to the grade (potentially a lower (BH)max, higher suffix grade) that survives that environment without drifting down the demagnetization curve toward its knee.
The number on the spec sheet is a starting point for a conversation, not the answer to it. The right grade is the one that matches your temperature envelope and mechanical loads first, and your strength target second.
Not sure which grade fits your design? That's exactly the kind of question our engineering team fields at the concept stage, before tooling gets cut, not after.
