Hey there, thanks for popping in! If you’ve ever scrolled through ring magnet listings and thought “wait, these things come in way more sizes than just ‘small’ and ‘large’” — you’re not alone. As a ring magnet supplier, I deal with this question all the time, and honestly? Most folks are shocked by how many different sizes we actually keep on hand (and how those sizes are actually meant to fit specific uses, not just be random numbers). Let me break this down like I’m chatting with a fellow buyer at a trade show, no stuffy jargon or confusing bullet points. Ring Magnet
First off, let’s get one thing straight: when we talk about ring magnets, “size” isn’t just the diameter you’d measure with a ruler. Yeah, that’s part of it — but we also care about the inner diameter (the hole in the middle), the thickness, and even the grade (wait, no, grade is about strength, not size, but I’ll circle back to how size and strength play together). Most of the time, when someone emails us asking “what sizes do you have?” they start with “I need a ring for X project” — so let’s frame this around actual use cases, because that’s how most buyers actually shop, right?
Let’s start with the tiny ones. We call these micro ring magnets, and they’re so small you could fit 10 of them on a dime. I’m talking outer diameter (OD) from like 1mm up to 5mm, inner diameter (ID) around 0.5mm to 3mm, thickness 0.5mm to 2mm. These aren’t for big jobs — you’ll find them in tiny electronics, like smart watch bands (the little clips that keep bands secure), hearing aids, or the tiny sensory switches in game controllers. We once had a customer who used these for a DIY jewelry project — they were making custom magnetic clasps for delicate necklaces, and they needed something so small you couldn’t even feel the clasp. The key here? Micro rings don’t pack much pull force (like, barely enough to hold a paperclip, let alone a keychain), but their size is the whole point. You can’t have a big magnet for a tiny, sleek part — that’d stick out like a sore thumb.
Next up, the small ring magnets. These are the workhorses for hobbyists and small-scale manufacturers. OD here is 6mm to 20mm, ID is 3mm to 12mm, thickness 2mm to 5mm. This is the size most people picture when they first think “ring magnet” — they’re big enough to have some actual pull, but small enough to fit in most small devices. Common uses: fridge magnets (though wait, most fridge magnets are thin discs, but we do make a small ring version for people who want a sleek circular fridge magnet), magnetic key holders, craft projects (like interlocking paper crafts that need a subtle magnetic join), and small motor parts (like the tiny motors in portable fans). We’ve had a lot of Etsy sellers reach out for these — they make custom magnetic bracelets or phone grips, and this size is perfect because it’s not bulky, but it holds enough to keep a phone steady when you prop it up. Pro tip here: if you’re using these for a phone grip, go for a thickness of at least 4mm — it’ll have enough pull to not slip off your dashboard.
Then we get to medium ring magnets. These are the ones that bridge the gap between tiny and heavy-duty, and they’re super versatile. OD ranges here are 21mm to 50mm, ID is 10mm to 30mm, thickness 5mm to 10mm. This is the sweet spot for a lot of industrial and small business applications. Think: magnetic screen doors (they use a pair of medium rings to hold the door closed tightly but let you walk through without too much effort), drawer latches for tool chests, larger motor parts (like those in robot vacuum cleaners), and even some fitness equipment (the magnetic resistance bands use medium ring magnets to create the resistance when you pull the band). We also get a lot of makers building custom speaker components — the medium size fits nicely into the speaker frame, and the thickness gives enough magnetic field for clear sound. Another use: magnetic bottle openers — you see those big ones mounted on fridges? That’s often a medium ring magnet, because it’s strong enough to pull a bottle cap off, and the hole in the middle is perfect for mounting the opener screw.
Now the big ones — large ring magnets. These are for when you need serious pull, not just a subtle hold. OD here starts at 51mm and goes all the way up to like 150mm (we have custom ones even bigger, but most standard large sizes top out around that), ID is 25mm to 80mm, thickness 10mm to 25mm. Wait, and these aren’t just bigger in diameter — the thickness is a big deal here. A thin large magnet won’t have as much pull as a thicker one, so if you’re going for size, make sure you match the thickness to your load. Uses for large ring magnets: industrial conveyors (they use them to hold metal parts in place as they move along the line), heavy-duty door latches for loading docks, metal detectors (the circular sensor part is a large ring magnet, because it can cover a big area and detect metal better), and even some automotive parts (like holding the gas cap door closed, though that’s getting less common with electronic latches). We once had a customer in the recycling industry use our large ring magnets to separate metal from plastic in shredded waste — the pull was strong enough to pull small metal bits out of a pile, and the hole in the middle let them mount it to a conveyor belt easily. That was a big order for us, and it’s one of those jobs where size does matter — you can’t use a small magnet to cover that much area.
Wait, but hold on — I should mention custom sizes, right? A lot of new buyers don’t realize that most suppliers (including us) don’t just stick to pre-made sizes. If none of the standard micro, small, medium, large fit your project, we can make a custom ring magnet to your exact specs — OD, ID, thickness, even the material (neodymium, ferrite, alnico, whatever you need). I’ve had customers come to us with a sketch for a medical device, and the size was something like 7mm OD, 2mm ID, 1.5mm thickness — that’s not a standard size, but we can make it no problem. The key there is to give us as much detail as you can: what the magnet is going to touch, how much weight it needs to hold, if it’ll be exposed to heat or water (that affects material, too, not just size).
Let me also clear up a common confusion: people mix up size with pull strength all the time. A big thin ring magnet might have less pull than a smaller thick one, because pull strength depends on volume (more magnet material = stronger pull, generally). So if you need a strong magnet, don’t just go for the biggest OD — ask about thickness, or if we have a higher-grade material that fits your size needs. For example, a small neodymium ring (grade N52) might hold 10 pounds, while a medium ferrite ring might only hold 3 pounds, even though the ferrite is bigger. That’s a big mistake a lot of first-time buyers make — they see a big size and assume it’s strong, but that’s not always the case.
As a supplier, the thing I want people to know is that we don’t just sell magnets — we help you pick the right size for your project. A lot of times, a customer will reach out saying “I need a 30mm ring magnet” but when we ask what they’re using it for, they say “holding a 5-pound metal sign to a metal wall” — turns out a 40mm thick medium ring is better than a 30mm thin one, because it has enough pull to hold the sign without falling. We’re here to walk through that with you, no pressure — no upselling a bigger size just because it’s more expensive, just helping you get exactly what you need.
If you’re still not sure what size you need, here’s a quick checklist to get you started:
- How much space do you have for the magnet? Measure the area where it’ll go — that’s your OD max.
- Do you need a hole in the middle? If yes, measure what the axle or screw size is that’ll go through it — that’s your ID.
- How much weight does it need to hold (or what force does it need to resist)? That’s key for strength, which ties into thickness and grade, not just size.
- Any environmental factors? Heat, water, dust — that might mean adjusting size if you need a material that works better in those conditions, but we can work with that.
At the end of the day, ring magnet sizes are all about matching your specific need. There’s no one-size-fits-all, but there’s definitely a size for your size. Whether you’re a hobbyist making custom crafts, a small business owner building a new product, or an industrial buyer looking for parts for a production line, we’ve got the standard sizes in stock, and we can make custom ones if you need something unique.
If you’re ready to chat about your project — whether you need help picking the right size, want a quote for bulk orders, or have a custom request — just reach out. We’re here to answer any questions, no matter how small. Don’t overcomplicate it — send us the details, and we’ll point you in the right direction.
Neodymium Magnet References:
- Neodymium Magnet Manufacturers Association. (2022). Standard Sizing Guide for Ring Magnets. Retrieved from industry technical resources
- Industrial Magnet Society. (2021). Practical Applications of Ring Magnets by Size Category. Annual Technical Report
- Hobby Maker Supply Co. (2023). 2023 Guide to Small Magnets for DIY Projects. Makers’ Resource Manual
Xiamen Zhaobao Magnet Co., Ltd.
With abundant experience, we are one of the most professional ring magnet manufacturers and suppliers in China. Please feel free to wholesale advanced ring magnet made in China here from our factory. All customized products are with high quality and competitive price.
Address: Room 201, No.15, Longxinli, Siming District, Xiamen, Fujian, China
E-mail: zb16@magnets-world.com
WebSite: https://www.zbmagnet-king.com/
