Magnetic Field Converter

Magnetic flux density is measured in Tesla (SI) or Gauss (CGS), with the relationship 1 T = 10,000 G. Earth's field at the surface runs about 25–65 microtesla, an MRI machine 1.5–3 T, and a refrigerator magnet around 5 mT.

This converter handles Tesla, milliTesla, microTesla, and Gauss in both directions. Useful for physics work where source material mixes SI and CGS conventions freely.

The Tesla, named for Nikola Tesla, was adopted by the General Conference on Weights and Measures in 1960. One Tesla equals one weber per square meter, or equivalently one volt-second per square meter. The Gauss, named for Carl Friedrich Gauss, predates SI and persists in geophysics, astronomy, and older physics literature where centimeter-gram-second units never fully gave way. The conversion 1 T = 10,000 G is exact by definition; submultiples (mT, μT, nT) and the geophysicist's gamma (1 γ = 1 nT = 10⁻⁵ G) all interconvert without loss.

A worked example: Earth's magnetic field at mid-latitudes runs roughly 50 μT, which is 0.5 G or 50,000 nT (also 50,000 γ). A neodymium fridge magnet at its surface is about 0.5 T (5,000 G) — ten thousand times stronger than the planetary field. A clinical 3 T MRI scanner produces 60,000 times Earth's field at its bore center. The Sun's surface field varies from 1–2 G in quiet regions to several thousand G in sunspots; magnetar surface fields reach 10⁹ T, the strongest known in the universe.

Limitations: the converter handles flux density (B-field), not the related but distinct H-field (magnetic field strength, A/m or oersted) or magnetic flux (weber, maxwell). In vacuum or non-magnetic materials B and H are proportional, but in ferromagnetic media they're not — confusing them is a common error in transformer and motor design. The converter also doesn't handle vector quantities or directional components; flux density is a vector in physics, scalar magnitude here.