A tesla (T) is the SI unit for measuring magnetic flux density—essentially how strong a magnetic field is in a given area. One tesla equals one weber per square meter.
In everyday contexts, you’re more likely to encounter microteslas (μT) or milligauss (mG) when measuring EMF from household sources like power lines or appliances.
A tesla measures magnetic field strength—specifically, the intensity of a magnetic field passing through a given area. Named after inventor Nikola Tesla, it’s the standard international unit used in scientific contexts.
In the EMF world, you’ll encounter teslas when discussing magnetic field exposure from power lines, appliances, and electronic devices. The key point is that one tesla is actually a very large unit. Earth’s natural magnetic field, for comparison, measures only about 25-65 microteslas at the surface.
Most household EMF measurements use microteslas (μT) or the older unit milligauss (mG) because the numbers are more practical. The conversion is straightforward: 1 microtesla equals 10 milligauss. So when you see an EMF meter reading of 1 mG, that’s 0.1 μT.
Why does this matter? Because understanding the units helps you interpret EMF readings and compare them to safety guidelines. Many building biology standards suggest keeping magnetic field exposure below 1 mG (0.1 μT) in sleeping areas. Medical MRI machines, by contrast, use fields of 1.5-3 teslas—millions of times stronger than typical household exposure.
When you’re testing EMF levels in your home with a gauss meter, you’re measuring this same magnetic flux density that the tesla quantifies—just expressed in more convenient units for the relatively weak fields we encounter in daily life.
