Standard United States pennies do not stick to magnets. Whether you try it with a penny minted last year or one from 1960, a refrigerator magnet or a strong rare-earth magnet, the coin will simply fall away. The reason comes down to what pennies are made of: copper and zinc, neither of which is ferromagnetic. There is, however, one famous exception in the history of American coinage, and pennies from other countries sometimes tell a completely different story.
What Pennies Are Actually Made Of
The composition of the US penny has changed over the centuries, but none of its formulations have included the metals that respond strongly to magnets. From 1857 through 1982, pennies were primarily copper, with small amounts of tin or zinc mixed in. The classic Lincoln cent that most people picture was 95% copper and 5% zinc. In 1982, the US Mint switched to a much cheaper design: a zinc core with a thin copper plating. Modern pennies are 97.5% zinc and only 2.5% copper by weight. Pick one up and it looks and feels like copper, but it is overwhelmingly zinc on the inside.
Neither copper nor zinc is attracted to magnets in any way you’d notice with your hands. Both metals are classified as diamagnetic, meaning they generate a tiny opposing field when exposed to a magnet. Copper’s volume magnetic susceptibility is about −9.7 × 10⁻⁶, an extremely small negative value that makes it very weakly repelled by a magnetic field rather than attracted to one.1IOP Publishing. Everything can be magnetized: simulating diamagnetic and paramagnetic response of everyday materials in magnetic balance experiments Zinc has a similarly tiny negative susceptibility. In practical terms, you would need an extraordinarily powerful laboratory magnet to detect the repulsion at all, and even then the penny would not visibly move. For everyday purposes, copper and zinc behave as though magnets do not exist.
Why Only Certain Metals Stick
The metals that noticeably cling to a magnet are called ferromagnetic. Iron, nickel, and cobalt are the three common ferromagnetic elements at room temperature. Their atomic structure allows large groups of atoms to align their tiny magnetic fields in the same direction, producing a strong enough collective pull that you can feel it in your fingers. Steel, which is mostly iron, sticks firmly to magnets. So does pure nickel. Alloys containing large amounts of these metals generally stick as well, though the strength of the attraction depends on the exact mix.
Copper and zinc atoms do not cooperate this way. Their electrons are arranged so that any magnetic moment in one atom is canceled out by its neighbors. The result is that diamagnetic response: instead of being pulled in, the material is pushed away by an amount so small it takes sensitive instruments to measure.1IOP Publishing. Everything can be magnetized: simulating diamagnetic and paramagnetic response of everyday materials in magnetic balance experiments A penny made entirely of copper, or entirely of zinc, or of any combination of the two, will never stick to a household magnet.
The 1943 Steel Penny
There is one year in which American pennies will stick to a magnet, and coin collectors know it well. In 1943, the United States was deep in World War II, and copper was desperately needed for ammunition casings and other military hardware. The Mint switched to zinc-coated steel for that single year. These 1943 steel cents look grayish-silver rather than the usual copper color, and they cling to a magnet immediately. Over a billion of them were produced across the Philadelphia, Denver, and San Francisco mints, so they are not especially rare, but they remain popular collectibles precisely because of their unusual composition and magnetic behavior.
The Mint returned to a copper-based alloy in 1944, using recycled brass shell casings to conserve resources. A small number of 1943 pennies were accidentally struck on leftover copper blanks, and a handful of 1944 pennies were struck on leftover steel blanks. These error coins are among the most valuable in American numismatics. If someone offers you a “1943 copper penny,” a magnet is one of the first tests experts suggest: a genuine 1943 copper cent will not stick to a magnet, while a common steel cent that has been fraudulently altered to look copper-colored will.
Pennies from Other Countries
The question of whether a “penny” sticks to a magnet gets more interesting when you look beyond the United States. Several countries have minted low-denomination coins using steel, and those coins respond to magnets just like the 1943 US version.
The United Kingdom’s one-penny and two-pence coins were solid bronze for most of the 20th century, but since 1992 the Royal Mint has produced them from copper-plated steel. A post-1992 British penny will stick to a magnet; a pre-1992 one will not. You can sort a jar of mixed UK pennies by date in seconds using nothing but a fridge magnet.
Canada retired its penny entirely in 2013, but the coins still circulate in change jars and collections. Canadian pennies went through multiple composition changes. Early versions were bronze, mid-century versions were a copper-zinc alloy, and later issues used copper-plated zinc or copper-plated steel. The steel-core versions, minted in certain years from 1999 onward, stick to magnets. If you have a pile of Canadian pennies and want to know which are steel, a magnet sorts them out instantly.
The Euro one-cent coin is also copper-plated steel and will cling to a magnet. Many other countries that still produce small-denomination coins have made the same switch to steel cores for cost reasons. The pattern is consistent: if a coin’s core is steel (an iron alloy), it sticks. If the core is copper, zinc, bronze, or brass, it does not.
The Eddy Current Trick
Even though a regular US penny will not stick to a magnet, there is a striking demonstration you can do with copper-rich coins and a strong neodymium magnet. If you slide a powerful rare-earth magnet across the surface of a pre-1982 penny, or roll the magnet slowly past a stack of copper pennies, you’ll notice the magnet seems to drag or slow down, as if the penny is resisting its motion. The penny is not becoming magnetic. What’s happening is that the moving magnetic field induces tiny electrical currents, called eddy currents, inside the copper. Those currents generate their own magnetic field, which opposes the magnet’s motion. The effect is more pronounced with thicker pieces of copper or with stronger magnets.
This phenomenon is the basis for a popular physics demonstration: drop a strong magnet through a copper pipe, and it floats downward in slow motion rather than falling freely. The penny version is subtler because a single coin is thin, but it is the same underlying physics. The key point is that this braking effect requires relative motion between the magnet and the conductor. Set a magnet on top of a penny and leave it still, and nothing happens. There is no static attraction. The coin and the magnet simply sit there, indifferent to each other.
Post-1982 pennies, being mostly zinc with just a skin of copper, produce a much weaker eddy current effect. Zinc is a poorer electrical conductor than copper, so less current flows, and the braking force is smaller. If you try the slow-magnet-drag test on a modern penny versus a pre-1982 one, the difference is noticeable. This is another informal way to sort older pennies from newer ones without looking at the date.
Using a Magnet to Test Coins
The magnet test is one of the simplest tools in a coin collector’s kit, and it works because the principle is binary: either a coin’s core is ferromagnetic or it is not. For US pennies, the test answers a few useful questions.
- Identifying 1943 steel cents: If a grayish penny sticks firmly to a magnet, it is almost certainly a genuine 1943 steel cent. If it does not stick, it may be a 1943 copper error coin (extremely rare and valuable) or a coin from another year that has been altered.
- Spotting counterfeits: Some counterfeit coins are made from steel or iron and then plated to look authentic. A magnet will catch these immediately. A genuine pre-1982 penny should not react to a magnet at all.
- Sorting foreign coins: In a mixed jar of international change, a magnet quickly separates steel-core coins from copper or brass ones.
The magnet test is not foolproof for every authentication scenario. A coin made from a non-ferromagnetic metal that is not the correct alloy for the genuine article will pass the magnet test while still being fake. Nickel is ferromagnetic, so a counterfeit coin made from nickel would stick even though the original might not. Professional coin grading involves weight measurements, diameter checks, and visual inspection of fine details in addition to the magnet test. But as a first screening step, dragging a magnet across a suspicious coin takes two seconds and eliminates a wide range of fakes.
Why the US Mint Has Not Switched to Steel
Given that many other countries have moved to steel-core coins to save money, you might wonder why the US still uses zinc. The economics of penny production have been a source of public debate for years. It costs more than one cent to manufacture a single penny, and this has been true for well over a decade. The zinc industry, which supplies the raw material for modern pennies, has lobbied to keep the current composition. Various proposals have surfaced in Congress over the years to change the penny’s makeup, replace it with steel, or eliminate it altogether.
Steel would be cheaper and would make the penny magnetic, which could actually help with vending machines and automated coin-sorting. But any composition change involves retooling at the Mint, adjusting every coin-accepting machine in the country, and navigating political resistance from industries tied to the current materials. The 1943 experiment showed it can be done, but the wartime urgency that drove that decision is not present today, and inertia has kept the zinc penny in production.
Several countries that have eliminated their lowest-denomination coin, including Canada and Australia, found that the sky did not fall. Prices are simply rounded to the nearest five-cent increment for cash transactions, while electronic payments remain exact. If the US ever follows suit, the question of whether a penny sticks to a magnet will become purely historical.
Other US Coins and Their Magnetic Behavior
While we are on the subject, none of the other currently circulating US coins stick to magnets either. Nickels might seem like a candidate given their name, but the US five-cent piece is 75% copper and only 25% nickel. That proportion of nickel in a copper matrix is not enough to make the alloy ferromagnetic. Dimes, quarters, and half dollars are clad coins with a copper core and outer layers of a copper-nickel alloy, and none of them are magnetic. The dollar coins (Sacagawea, Presidential series) use a manganese-brass alloy over a copper core. Also not magnetic.
There is one historical exception beyond the 1943 penny. During World War II, the composition of the nickel was also changed: from 1942 to 1945, “war nickels” were made from an alloy of copper, silver, and manganese, eliminating nickel entirely for the war effort. Ironically, these war nickels are even less magnetic than regular nickels, since they traded out the one weakly ferromagnetic ingredient. You can identify them by the large mintmark above Monticello on the reverse. They are common enough to turn up in pocket change occasionally, particularly since their silver content has not yet motivated everyone to pull them from circulation.
The broader point is that the US Mint has historically avoided ferromagnetic alloys in its circulating coinage. This is partly tradition and partly because the electromagnetic signatures of coins matter for vending machines and automated sorting equipment. Machines that accept coins rely on a consistent electrical conductivity and density profile for each denomination. Introducing a ferromagnetic coin into the mix would require recalibrating every machine in the country, which is one more reason the composition of US coins changes slowly and reluctantly.
When a Penny Does Something Unexpected Near a Magnet
Occasionally someone reports that a penny “stuck” to a magnet, and their confusion is genuine. A few explanations cover most of these cases. First, surface moisture or oils can create a slight adhesion between a coin and a smooth magnet face that feels like magnetic attraction but is really just stickiness. Second, if the coin is foreign and happens to be the same size as a US penny, it may have a steel core. Third, some novelty or commemorative coins are made from ferromagnetic alloys and can be mistaken for standard pennies. And fourth, very strong neodymium magnets can sometimes seem to “grab” a copper coin because of the eddy current braking described above, especially if the coin is sliding along a surface and suddenly decelerates near the magnet. The coin is not sticking in the conventional sense, but the braking force can feel surprisingly firm.
If you want to confirm for yourself, find a known US penny from any year other than 1943, hold it against a refrigerator magnet, and let go. It will drop straight down, every time. The science is not complicated, and the test is satisfyingly definitive. Copper and zinc simply do not care about magnets, and no amount of hoping will make them stick.