Magnetic Field Converter

Magnet labels, Hall-sensor data sheets, MRI specifications, and lab notes often mix tesla, gauss, and oersted. This calculator converts among the three units used by the form: Tesla (T), Gauss (G), and Oersted (Oe, vacuum/air). Enter a nonnegative Value, select the From unit, select the To unit, and the result panel shows the chosen conversion plus all supported equivalents.

The tesla is the SI derived unit used here as the base. It describes magnetic flux density, often called magnetic field in practical converter contexts. Gauss is a CGS unit still seen in magnet catalogs, field meters, and geophysics. Oersted is historically a unit of magnetic field strength, not the same physical quantity as tesla in every material. The calculator deliberately follows its calculation: it treats gauss and oersted as the same factor relative to tesla and warns that the oersted relationship assumes vacuum or air where relative permeability is approximately 1.

Exact conversion method

The calculation stores factors relative to tesla:

It multiplies the entered value by the source factor and divides by the target factor:

$\text{field in tesla} = \text{value} \text{ } \times \text{ } \text{source factor}$

$\text{converted field} = \frac{\text{field in tesla}}{\text{target factor}}$

Results are formatted to six decimal places. Because the form accepts only nonnegative values, it is best thought of as a magnitude converter. Direction, polarity, vector components, and probe orientation must be tracked outside the unit conversion.

Example

Convert 0.032 T to gauss. The source factor for tesla is 1:

$0.032 \text{ } \text{T} \text{ } \times \text{ } 1 = 0.032 \text{ } \text{T}$

The target factor for gauss is 0.0001:

$\frac{0.032}{0.0001} = 320$

The calculator displays 320.000000 G. In the all-units list, the same input also appears as 0.032000 T and 320.000000 Oe because the form uses the same 0.0001 tesla factor for oersted under its vacuum or air assumption. That is fine for a quick unit comparison in air, but it is not a substitute for a permeability-specific model inside iron, ferrite, or other magnetic materials.

Where these units show up

Tesla is common for SI physics, MRI field strengths, high-field magnets, accelerators, and specifications where the field is large enough that gauss would produce unwieldy numbers. A 1.5 T or 3 T MRI magnet is clearer in tesla than in tens of thousands of gauss.

Gauss remains convenient for smaller fields and for many permanent magnets. Earth’s magnetic field, residual magnetism, reed switch operate points, Hall sensor ranges, and hobby magnet measurements are often discussed in gauss. The conversion to tesla is simple: move four decimal places because 1 G equals 0.0001 T.

Oersted appears in CGS magnetic field strength discussions, magnetization curves, and older material data. This converter’s oersted output is deliberately limited to vacuum or air behavior. If a material’s relative permeability changes with field, frequency, or saturation, Oe, G, and T relationships require more than a one-line unit factor.

Reference table

Pitfalls and related tools

Do not confuse magnetic field with magnetic flux, force, current, or energy. A coil’s field depends on geometry and current; converting tesla to gauss does not tell you the current needed to create it. Use the electric current converter to align current units, the force converter when magnetic force is reported in newtons or pounds-force, and the energy converter when magnet systems are discussed in joules. For RF and AC applications, frequency can also matter, so the frequency converter may be a useful companion.

Measurement details matter. Hall probes have axis markings, range limits, offsets, temperature drift, and calibration uncertainty. Permanent magnets can have steep field gradients, so moving the probe a few millimeters can change the reading. When converting published values, check whether the source uses peak, RMS, surface, gap, axial, or average field.

Also check whether a specification is describing a static field or a changing field. A DC holding magnet, a mains transformer core, and an RF inductor can all be discussed with magnetic units, but their design questions are different. The unit conversion can make the number readable; it cannot decide whether eddy currents, heating, shielding, saturation, or time-varying induction are acceptable.

Accuracy and limits

The calculator keeps the defined or cited relationship through the calculation and rounds only the displayed result. A converted number does not become more precise than the source measurement. Keep additional digits for chained calculations, then round to the precision justified by the original value; also preserve any reference basis or notation convention named with the input.

Sources

• NIST, SI Units — SI framework for derived units such as tesla.
• NIST, Guide for the Use of the International System of Units — SI usage guidance and non-SI unit context.
• BIPM, Measurement units — international reference for SI measurement units.