Magnets stick to iron and most steels, and best to thick, bare mild steel. They don't stick to aluminum, copper, brass, wood, glass or plastic, and the most common stainless steels (grades 304 and 316) are barely magnetic or not magnetic at all.
Which metals do magnets stick to?
| Material | Does a magnet stick? | Notes |
|---|---|---|
| Mild (low-carbon) steel | Yes, best | Thick, flat and bare gives the highest hold |
| Cast iron | Yes | Holds less than mild steel |
| Alloyed and hardened steels | Yes | Hold less than mild steel |
| Stainless steel 304 and 316 (austenitic) | Barely or not | Can become slightly magnetic where it has been bent or cold-worked |
| Ferritic stainless steel, such as 409 and 430 | Yes | Magnetic |
| Martensitic stainless steel, such as 420 | Yes | Magnetic |
| Aluminum, copper, brass | No | Not magnetic |
| Wood, glass, plastic | No | Not magnetic |
Sources: our technical data page, section 5, and the Australian Stainless Steel Development Association (ASSDA) on the magnetic response of stainless steels.
Do magnets stick to stainless steel?
It depends on the grade. The most common stainless steels, 304 and 316, are austenitic: they are barely magnetic or not magnetic at all, although bending or cold-working can make them slightly magnetic in places. Ferritic grades such as 409 and 430 and martensitic grades such as 420 are magnetic. That's why a magnet holds on one stainless steel fridge, sink or tool and not on another. If you can't find out the grade, test it with a small magnet before you order a larger one.
Do magnets stick to aluminum?
No. Aluminum isn't magnetic, and neither are copper and brass. To attach a magnet to aluminum or another non-magnetic surface, add a piece of steel for it to hold onto (see below), or glue or screw the magnet itself in place and let it hold a steel part.
Why does a magnet hold less on sheet metal?
The pull force listed for a magnet is measured straight off a thick, flat, bare steel plate. Thin steel can't take up the magnet's full field, so a strong magnet holds noticeably less on sheet metal than its rating. Paint, powder coating, rust, dirt and a rubber coating all act as an air gap and reduce the hold further, and so do rough or curved surfaces. A magnet that has to stop something sliding down a vertical surface holds much less than its straight-pull rating.
These are rated pull forces from our product pages, measured on thick steel:
| Product | Rated pull force on thick steel (lb) | (kg) |
|---|---|---|
| Neodymium Disc Magnet 10 x 3 mm N48 | approx. 3.5 | 1.6 |
| Neodymium Disc Magnet 20 x 5 mm, Nickel-Plated | approx. 10.8 | 4.9 |
| Countersunk Neodymium Pot Magnet 20 x 6 mm | approx. 24.3 | 11 |
| Countersunk Neodymium Pot Magnet 32 x 8 mm | approx. 46.3 | 21 |
| Rubber-Coated Neodymium Pot Magnet 43 mm with M4 Internal Thread | approx. 30.9 | 14 |
| Rubber-Coated Neodymium Pot Magnet 88 mm with M8 Internal Thread | approx. 121.3 | 55 |
On thin sheet metal, painted steel or a vertical surface, expect less. See magnet pull force explained and our pull force chart.
How can I make a non-magnetic surface magnetic?
Fix a piece of steel to it for the magnet to hold onto:
- Steel washers. Our countersunk steel washers come in 10 sizes from 8 to 60 mm outer diameter. They aren't magnets: screw or glue one to wood, aluminum or plastic as the counterpart for a magnet. They're in our magnet accessories.
- Ferrous self-adhesive sheet. The A4 ferrous sheet (0.3 mm) and A3 version turn a smooth surface into one that magnetic sheet and tape stick to. It's thin, so a strong magnet holds much less on it than on thick steel.
- Two magnets. Where you can reach both sides, a magnet on each side holds through a thin non-magnetic panel. The thicker the panel, the weaker the hold.
What about a surface that isn't flat or bare?
Use a magnet with a larger face, or a pot magnet, and keep the contact surface clean. On painted or delicate surfaces, a rubber-coated magnet protects the finish and resists sliding, though it holds less than an uncoated magnet of the same size. See neodymium magnet coatings.
Related guides
- Pot magnets (cup magnets) explained
- How to choose a magnet
- How to glue neodymium magnets
- Magnets for signs and displays
Need help choosing? Browse neodymium magnets or countersunk magnets. For larger quantities or a size, grade or coating we don't list, request a quote. In-stock orders ship from US stock the same working day and arrive in about 5 business days; shipping is $5.99 under $50 and free from $50 (see US shipping).
Safety: strong magnets can pinch fingers and skin, and can chip or shatter if they snap together. Keep them away from pacemakers and other medical implants. Our products are not toys: keep small magnets out of the reach of children. See our magnet safety page.
Questions and answers
Do magnets stick to stainless steel?
Only to some grades. The common grades 304 and 316 are barely magnetic or not magnetic at all, while ferritic grades such as 430 and martensitic grades such as 420 are magnetic.
Why won't a magnet stick to my stainless steel fridge?
The front is probably an austenitic stainless steel such as 304, which is barely magnetic. Fronts made of a ferritic grade such as 430 do attract magnets. A steel washer or ferrous self-adhesive sheet gives a magnet something to hold onto.
Do magnets stick to aluminum?
No. Aluminum isn't magnetic. Fix a steel washer or ferrous sheet to it, or mount the magnet itself and let it hold a steel part.
Do magnets stick to copper or brass?
No. Copper and brass aren't magnetic.
Is cast iron magnetic?
Yes. Magnets stick to cast iron, but they hold less than on mild steel.
Do magnets work through paint?
Yes, but paint and powder coating act as an air gap, so the magnet holds less than on bare steel.
Can a magnet hold on thin sheet metal?
Yes, but less than its rating. Pull force is measured on thick steel, and thin sheet can't take up a strong magnet's full field.