Magnetic flux density

The International System (SI) unit of field "magnetic flux density" is the tesla (T).

A magnetic field of one tesla is relatively strong. That is why magnetic fields are also expressed in militesla (mT) and microtesla (µT).

1 T = 1 000 mT = 1 000 000 µT

To facilitate comparaisons GreenFacts has systematically used the unit mT in its static field summaries.

Typical values for static magnetic fields
(the most commonly used unit is marked in grey)

Magnetic field T mT µT
Earth's magnetic field intensity at its surface   0.035-
0.070 mT
35 - 70 µT
Inside electric trains up to 0.002 T up to 2 mT up to 2000 µT
Aluminium production up to 0.06 T up to 60 mT up to 60000 µT
Magnetic Resonance Imagning (MRI) scanner used in a clinical setting 0.2 -
3 T
3000 mT
Fields reported to induce vertigo and phosphenes
in people moving in them
above 2-3 T above 2000-3000 mT  
Fields for which health effects have been studied so far up to 8 T up to 8000 mT  
Strongest fields now being developed for clinical imaging up to 9.4 T up to 9400 mT  

In the International System (SI) one tesla (1 T) is defined as the field intensity generating one newton of force per ampere of current per meter of conductor:

T = Nw · A-1 · m-1 = kg · s-2 · A-1

The International Bureau of Weights and Measures (BIPM) provides further information on the International System of Units (SI) at  and on prefixes of the International System of Units (SI) at 

Related publication:
Static Fields homeStatic Fields
Other Figures & Tables on this publication:

Table 1 : Recommendations for research

Static electric fields of TV sets and computer screens

Magnetic flux density