Gauss, milligauss and microtesla
A gaussmeter measures magnetic field strength. The unit you will see on most consumer meters is the milligauss (mG); scientific and European sources use the microtesla (µT):
- 1 µT = 10 mG
- 1 mG = 0.1 µT
- 1 gauss = 1,000 mG
For context, typical background in a room away from wiring is well under 1 mG, while standing next to an operating electrical panel or an unbalanced circuit can read tens of mG. What matters for an assessment is not a single number but where the field is elevated and whether people spend hours there.
AC vs DC gaussmeters — do not buy the wrong one
| AC gaussmeter | DC gaussmeter | |
|---|---|---|
| Measures | Alternating fields, 50/60 Hz and harmonics | Static fields |
| Sources | House wiring, panels, transformers, motors, power lines | Permanent magnets, magnetised steel, magnetic therapy products, the earth's field |
| Use case | Home and workplace EMF surveys | Magnet testing, industrial and lab work |
Almost everyone searching for a "gaussmeter" for home EMF work needs the AC type. A DC gaussmeter will read close to nothing next to live wiring, and an AC meter will read nothing next to a permanent magnet.
Single-axis vs triple-axis
A single-axis probe only senses the field component along its own axis, so a reading depends on how you hold it: you must rotate through all three orientations and take the maximum, or you will under-report. A triple-axis meter such as the LATNEX MG-2000T reads all three axes and reports the resultant, which is both faster and far harder to get wrong. If you are producing readings anyone else will rely on, use triple-axis.
Meters for magnetic field work
- Dedicated gaussmeters — LATNEX MG-300 for straightforward hot-spot finding; MG-2000T triple-axis for survey work.
- Low-frequency specialists — Gigahertz Solutions ME3030B and ME3830B, which read magnetic and electric fields with the resolution building-biology protocols expect.
- Three-field meters — the TriField TF2 and similar cover magnetic, electric and RF in one device; the right choice if this is your only meter. See the full meter range.
How to survey magnetic fields properly
- Measure where people actually are for hours: bed, desk, sofa, child's room — at body height, not at the wall.
- Walk slowly. Magnetic fields from wiring fall off very quickly with distance; a hot spot can be a few centimetres wide.
- Measure at high and low household load (evening vs midday) — the field scales with current.
- Trace the source: follow rising readings back to a panel, a circuit run, a transformer, a subpanel or an appliance motor.
- Note the readings and keep them, so you can prove any change later.
Reducing a magnetic field
This is the important difference from RF: shielding paint and metallised fabric do not block low-frequency magnetic fields. The options, roughly in order of cost-effectiveness, are:
- Distance. Move the bed or desk away from the source; the drop-off is steep.
- Fix the cause. Net current on a circuit — from wiring errors, shared neutrals or knob-and-tube runs — produces fields that shielding cannot fix but an electrician can.
- High-permeability shielding. Where the source cannot be moved, magnetic field shielding films and alloys (WOREMOR WMF/NeoMag, MAGINDUCT, G-IRON ARMOFLEX) redirect the field. These must cover the source or the target closely to work — a distant sheet does very little.
Then re-measure in the same spots. Related: EMF meter buying guide · safe EMF levels for humans.