Do Magnets Get Stronger When Stacked?

Many people notice that when using magnets, stacking several together seems to make them “stronger” than a single magnet. Is this true? Today, we'll explain the science behind this phenomenon and illustrate it with examples.

The magnetic force of a magnet primarily depends on its magnetic field strength and magnetic flux. When two or more magnets with the same poles facing each other are closely stacked, their magnetic fields combine in the same direction, forming a stronger overall magnetic field. This is akin to several small rivers merging into a larger one, naturally resulting in greater magnetic force.

For example, a single N35 grade neodymium magnet measuring 10mm in diameter and 2mm in thickness may exert a magnetic pull of approximately 1 kilogram. If five identical magnets are stacked together, the overall thickness becomes 10mm, strengthening the magnetic field and potentially increasing the magnetic pull to 3-4 kilograms.

The accompanying image shows a galvanized neodymium elliptical oval magnet.

Although the increase is not linear (a fivefold increase in thickness does not equate to a fivefold increase in suction), the cumulative effect is indeed significant.

We must also understand that a magnet's attraction depends not only on magnetic field strength but also closely on its contact area with the object being attracted. If the contact surface between the magnet and iron plate is very small, even a strong magnetic force may fail to produce a powerful holding force. Conversely, a larger contact surface allows more magnetic flux to pass through the attracted object, resulting in a more stable attraction.

For example, a circular magnet with a diameter of 20mm and a thickness of 2mm may exhibit greater magnetic force than a magnet measuring 10mm in diameter and 10mm in thickness. This is because the former possesses a larger contact area, allowing for more uniform distribution of magnetic force. If multiple small magnets are stacked into a cylindrical shape, the increase is limited to thickness while the contact area remains unchanged, resulting in only a marginal enhancement of magnetic force. However, if the magnets are laid side by side to expand the contact surface, the overall magnetic pull becomes significantly stronger.

So, the answer is that stacking magnets does indeed increase magnetic force, but more isn't necessarily better. Increasing the thickness of magnets concentrates the magnetic field, while increasing the contact area allows the magnetic force to be released more fully, enhancing the pulling force.

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