Gauss (G) is a unit of magnetic flux density used to describe the strength of a magnetic field at a specific point. In SI units, magnetic flux density is measured in tesla (T), and 10,000 gauss = 1 tesla. A gauss reading is useful for checking a magnet’s surface field, comparing magnetic field at a set distance, verifying assemblies, and performing production quality control.
One important distinction: a gauss reading is not the same thing as pull force, magnet grade, or the material property Br. The measured gauss value depends on the magnet’s material, geometry, magnetization direction, measurement distance, probe orientation, temperature, and surrounding magnetic circuit.
What Is Gauss a Measure Of?
Gauss measures magnetic flux density, commonly represented by the symbol B. It describes how concentrated a magnetic field is at the measurement location.
| Gauss | Tesla | Millitesla | Microtesla |
|---|---|---|---|
| 1 G | 0.0001 T | 0.1 mT | 100 µT |
| 10 G | 0.001 T | 1 mT | 1,000 µT |
| 100 G | 0.01 T | 10 mT | 10,000 µT |
| 1,000 G | 0.1 T | 100 mT | 100,000 µT |
| 10,000 G | 1 T | 1,000 mT | 1,000,000 µT |
Use our Magnetic Unit Converter to convert gauss to tesla, millitesla, oersted, kA/m and other engineering units.
Gauss vs. Tesla
Gauss and tesla measure the same physical quantity: magnetic flux density. Gauss belongs to the CGS system, while tesla is the SI unit.
- 1 tesla = 10,000 gauss
- 1 gauss = 0.0001 tesla
- 1 gauss = 0.1 millitesla
Gauss is still widely used in permanent-magnet specifications and field measurements because the values are convenient for many practical magnet applications.
Gauss vs. Oersted: B and H Are Not the Same
Gauss and oersted are often discussed together, but they represent different quantities. Gauss measures magnetic flux density (B), while oersted measures magnetic field strength (H) in the CGS system. In SI units, B is measured in tesla and H is measured in amperes per meter.
This distinction matters when reading magnet datasheets and B-H curves. Values such as Br, HcB, HcJ and BHmax describe different aspects of magnetic material performance and should not be treated as interchangeable.
How Is Gauss Measured?
A magnetic field is commonly measured using a gaussmeter or magnetometer. Most handheld gaussmeters used for permanent magnets rely on a Hall-effect sensor located in a probe.
1. Zero and Prepare the Gaussmeter
The instrument should be zeroed according to the manufacturer’s procedure and the correct measurement range selected. For comparative production testing, the same instrument, probe and setup should be used consistently.
2. Position the Probe
The probe is placed at a defined location relative to the magnet. Even a small change in distance or angle can materially change the reading, particularly near the magnet surface or edge.
3. Orient the Probe Correctly
Hall probes measure a component of the magnetic field. Axial and transverse probes respond to different field directions, so probe orientation must be controlled if readings are going to be compared against a specification.
4. Record the Peak or Specified-Location Reading
Depending on the inspection method, the operator may record a peak surface field, a value at the geometric center, or a field value at a defined air gap. A gauss specification is incomplete unless the measurement location and method are also defined.
What Is Surface Gauss?
Surface gauss is the magnetic flux density measured at or very near the surface of a magnet. It is influenced by more than the magnet grade alone.
Two magnets made from the same N52 material can have very different surface-gauss readings if their dimensions or magnetization directions are different. Likewise, a lower-grade magnet with a favorable geometry can produce a higher local surface field than a higher-grade magnet with a different shape.
Does Higher Gauss Mean a Stronger Magnet?
Not necessarily. A higher gauss reading means the magnetic flux density is higher at the particular point being measured. It does not by itself tell you the magnet’s total holding force or whether it will perform better in a specific assembly.
Pull force depends on magnet dimensions, contact area, air gap, target material, steel thickness, coating, surface condition and the magnetic circuit. For holding applications, use the Magnet Pull Force Calculator in addition to field measurements.
Is Gauss the Same as Magnet Grade?
No. A grade such as N35, N42 or N52 describes a range of intrinsic magnetic material properties. It does not specify a single surface-gauss value.
For example, N52 indicates a higher maximum energy product range than N35, but the gauss measured on a finished magnet still depends strongly on the finished geometry and measurement conditions. See our Neodymium Magnet Grade & Property Chart for material-level specifications.
Gauss vs. Br (Residual Induction)
This is one of the most common sources of confusion in permanent-magnet specifications. Br, or remanence, is an intrinsic material property measured under defined magnetic test conditions. A gaussmeter reading taken on the surface of a finished magnet is a local field measurement.
A material datasheet may list Br in gauss or tesla, but that does not mean a finished magnet made from that material will show the same number on a handheld gaussmeter. Geometry and the magnet’s operating point strongly influence the field outside the magnet.
Why Gauss Readings Change With Distance
The magnetic field outside a permanent magnet decreases as the distance from the magnet increases. The exact rate depends on geometry and where the measurement is taken.
For this reason, a specification such as “3,000 gauss” is incomplete unless it states where the reading is taken—for example, at the pole surface, 1 mm above the center of the pole, or at a defined location inside an assembly.
Factors That Affect a Gauss Reading
- Magnet material and grade
- Magnet dimensions and aspect ratio
- Magnetization direction
- Measurement distance or air gap
- Probe orientation and probe type
- Location on the magnet surface
- Nearby steel or other magnetic materials
- Temperature
- Magnetic history or partial demagnetization
How Gauss Measurement Is Used in Magnet Quality Control
Gauss measurement can be an effective production-control tool when the test setup is standardized. It is commonly used to confirm polarity, identify weak or partially magnetized parts, compare batches, verify magnetic assemblies and check field strength at a functional location.
For customer drawings or inspection plans, it is best to define the instrument, probe orientation, measurement location, air gap, temperature and acceptable range. Without those conditions, two valid measurements of the same magnet can produce different results.
Frequently Asked Questions About Gauss
What is gauss in simple terms?
Gauss is a unit that tells you how much magnetic flux density exists at a specific location. Higher gauss means a stronger local magnetic field at that measurement point.
How many gauss are in 1 tesla?
1 tesla equals 10,000 gauss.
Is 10,000 gauss a strong magnet?
10,000 gauss equals 1 tesla of magnetic flux density, which is a substantial field. However, a single gauss number is not enough to determine a magnet’s pull force or overall suitability because the measurement location and magnet geometry also matter.
How many gauss is an N52 magnet?
There is no single correct surface-gauss value for an N52 magnet. N52 describes the magnetic material grade, while the measured surface field depends on the magnet’s shape, dimensions, magnetization direction and measurement method.
Can I compare two magnets using surface gauss?
Yes, if both magnets are measured using the same instrument, probe orientation, position, air gap and temperature. Without a consistent fixture and method, surface-gauss comparisons can be misleading.
What instrument measures gauss?
A gaussmeter, typically using a Hall-effect probe, is commonly used to measure magnetic flux density in permanent-magnet applications.
