Magnetic Flux Density converter

The tesla is the SI unit used as the reference point for every entry in this table, and two other names are just the tesla by another route: a weber per square meter (Wb/m²) is identical to a tesla because flux density is flux divided by area, while a maxwell per square centimeter (Mx/cm²) is the CGS version of that same ratio, which is why it lines up with gauss rather than tesla. Gauss itself is the everyday CGS unit, and one tesla equals a clean 10,000 gauss.

Reading down the table, the prefixes track real differences in scale: nanotesla and its CGS twin "gamma" describe the faint variations geophysicists measure in Earth's field, microtesla covers Earth's field itself (around 50 µT, or 0.5 G) and the stray fields near household wiring, millitesla and kilogauss describe small permanent magnets, and whole teslas describe the field inside an MRI scanner or a research electromagnet.

The gauss-to-tesla rule is T = G × 0.0001, and the reverse direction multiplies by 10,000.

A typical craft or fridge magnet rated around 50 G converts to 0.005 T (5 mT). A clinical MRI magnet running at 3 T converts the other way to 30,000 G — a figure that reads more intuitively on an older gauss-calibrated meter, which is part of why gauss has stuck around in magnet marketing even though tesla is the formal SI unit. A smaller consumer magnet rated at 1,000 G (1 kG) converts to 0.1 T, which is why kilogauss and tenths of a tesla are often used interchangeably in magnet supplier catalogs.

Magnetic flux density is one of the few units ordinary people encounter directly: refrigerator and craft magnets are rated in gauss, MRI machines are named by their tesla rating, Hall-effect sensors in phones and cars report microtesla-scale changes, and electricians or health-and-safety assessors checking stray fields near power lines or induction cooktops usually work in milligauss, since that is the scale most exposure guidelines are written around. Older research and veterinary MRI documentation sometimes still lists field strength in kilogauss in archived records, even though the machines themselves are universally described in tesla today.

The most common confusion is treating Earth's field as negligible because "0.5 gauss" sounds tiny — in tesla that is 50 microtesla, exactly the scale sensitive magnetometers and compass chips are built to detect, so small-looking gauss numbers and small-looking microtesla numbers can describe a field that is very much not negligible for a sensor. It's also easy to confuse gamma with the unrelated gamma ray: here gamma is simply another name for the nanotesla, used mainly in geomagnetic survey data. Treating gauss and tesla readings from two different eras of literature as directly comparable without converting is one of the easiest ways to misjudge how strong a magnet actually is.

Weber per square meter and maxwell per square centimeter are the same flux-density idea written in SI and CGS area units respectively, and because a square meter is ten thousand times larger than a square centimeter, a weber per square meter numerically equals one tesla while a maxwell per square centimeter numerically equals one gauss — so those two entries don't need separate memorizing once the tesla-gauss relationship is clear. Anyone working from an older magnetic-circuit textbook that expresses flux density in Mx/cm² can treat the figure exactly as a gauss reading without any extra arithmetic.