What Does Gauss Mean, and How Is It Different From Pull Force?

Gauss measures

How concentrated the field is at one point

Pull force measures

How hard the magnet holds to thick steel

Unit conversion

10,000 gauss = 1 tesla

Best for choosing a holding magnet

Pull force

What Does Gauss Mean?

Gauss is a unit of magnetic flux density, named after the mathematician Carl Friedrich Gauss. Flux density describes how tightly a magnetic field is packed at a given point; picture how close together the field lines are. Earth’s field is about half a gauss, while the pole face of a neodymium magnet measures a few thousand.

The SI unit is the tesla (T): 1 T = 10,000 G, and 1 millitesla (mT) = 10 G.

Surface Gauss vs. Br

You’ll see two kinds of gauss figures for magnets:

• Surface field (surface gauss) is the field measured with a gaussmeter at the magnet’s pole face. For neodymium magnets it’s typically about 2,000 to 6,500 G, depending on shape.
• Residual flux density (Br), or remanence, is a property of the magnet material, measured in a closed magnetic circuit. N52 has a Br of about 14,300 to 14,800 G, and N42 about 12,900 to 13,300 G.

Measured at the center of its pole face, a magnet on its own reads no more than about half its Br, roughly 7,000 G for N52. So a “gauss rating” of 12,000 to 14,800 G describes the grade’s Br, not a reading you’d get on the magnet.

How Is Gauss Measured?

A gaussmeter uses a thin Hall-effect probe held flat against the center of a pole face. The reading depends on exactly where the probe sits, how far its sensor is from the surface, and whether it’s square to the face, so two meters can give somewhat different readings for the same magnet. See how the surface field is measured.

What Is Pull Force?

Pull force is the force needed to pull a magnet straight off a thick, flat, ground steel plate with no gap. It’s measured with a force gauge and listed in pounds on every product page. It’s the best-case holding force against steel; in real use, gaps, thin steel and sliding loads reduce it. See what pull force means and does a 20 lb magnet actually hold 20 lb?

Gauss vs. Pull Force: What’s the Difference?

Why Can Two Magnets with the Same Gauss Have Different Pull Force?

Gauss is measured at one point, while pull force reflects the whole magnet: the field across its entire face and how far that field reaches. Surface field depends mainly on a magnet’s proportions, so two discs with the same shape but different sizes read about the same. The larger one has far more face area and volume, so it pulls much harder.

Our N52 discs show the pattern. Calculated surface field at the center of the pole face, with listed pull force:

The 1 × 1/4 Inch disc reads lower gauss than the 1/2 × 1/4 Inch disc, yet pulls about 2.5 times harder. Thin, wide magnets have a lower surface field but plenty of pull because of their large face.

What Is a Good Gauss Rating for a Neodymium Magnet?

There isn’t one “good” number, because gauss depends so much on shape. For context:

At the same size, a higher grade raises both numbers: N52 has a higher Br than N42, so an N52 magnet has a stronger surface field and more pull than an N42 magnet of the same size. Making a magnet thicker raises its surface field; making it bigger raises its pull. See N42 vs. N52.

When Should I Use Gauss Instead of Pull Force?

Use pull force whenever the magnet has to hold something: mounting, closures, signs, hooks, or working out how many magnets you need. Use gauss when the field itself matters:

• Sensors and switches. Hall-effect sensors and reed switches trigger at a set field strength. What counts is the field at the sensor’s distance, which is far lower than at the surface.
• Safety distances. Medical-implant guidance is written in gauss: fields of 10 G (1 mT) or more can affect many pacemakers. See magnets near pacemakers and implants.
• Field reach and shielding. Gauss readings show how quickly a field fades with distance and how much gets through a shield. See how far a magnetic field reaches.
• Consistency checks. Comparing readings across magnets of the same size and grade is a quick way to check that a batch is consistent.

Buyer Takeaway

Gauss tells you how concentrated a magnet’s field is at its surface; pull force tells you how hard it holds to steel. If you’re choosing a magnet to hold something, compare pull force, then allow for gaps, thin steel and sliding loads. Use gauss for sensors, safety distances and field measurements, and read a very high “gauss rating” as the material’s Br rather than a surface reading.

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