# Orders of magnitude (magnetic field)

This page lists examples of magnetic induction B in teslas and gauss produced by various sources, grouped by orders of magnitude.

Note:

• Traditionally, magnetizing field H, is measured in amperes per meter.
• Magnetic induction B (also known as magnetic flux density) has the SI unit tesla [T or Wb/m2].[1]
• One tesla is equal to 104 gauss.
• Magnetic field drops off as the cube of the distance from a dipole source.

## Orders of Magnitude

These examples attempt to make the measuring point clear, usually the surface of the item mentioned.

List of orders of magnitude for magnetic fields
Factor (tesla) SI prefix Value (SI units) Value (CGS units) Item
10−18 attotesla 5 aT 50 fG SQUID magnetometers on Gravity Probe B gyroscopes measure fields at this level over several days of averaged measurements[2]
10−15 femtotesla 2 fT 20 pG SQUID magnetometers on Gravity Probe B gyros measure fields at this level in about one second
10−12 picotesla 100 fT to 1 pT 1 nG to 10 nG Human brain magnetic field
10−11 10 pT 100 nG In September 2006, NASA found "potholes" in the magnetic field in the heliosheath around our solar system that are 10 picoteslas as reported by Voyager 1[3]
10−9 nanotesla 100 pT to 10 nT 1 μG to 100 μG Magnetic field strength in the heliosphere
10−7 60 nT to 700 nT 600 μG to 7 mG Magnetic field produced by a toaster, in use, at a distance of 30 cm (1 ft)[4]
100 nT to 500 nT 1 mG to 5 mG Magnetic field produced by residential electric distribution lines (34.5 kV) at a distance of 30 cm (1 ft)[4][5]
10−6 microtesla 1.3 μT to 2.7 μT 13 mG to 27 mG Magnetic field produced by high power (500 kV) transmission lines at a distance of 30 m (100 ft)[5]
4 μT to 8 μT 40 mG to 80 mG Magnetic field produced by a microwave oven, in use, at a distance of 30 cm (1 ft)[4]
10−5   24 μT 240 mG Strength of magnetic tape near tape head
31 μT 310 mG Strength of Earth's magnetic field at 0° latitude (on the equator)
58 μT 580 mG Strength of Earth's magnetic field at 50° latitude
10−4 500 μT 5 G The suggested exposure limit for cardiac pacemakers by American Conference of Governmental Industrial Hygienists (ACGIH)
10−3 millitesla 5 mT 50 G The strength of a typical refrigerator magnet[6]
10−2 centitesla
10−1 decitesla 150 mT 1.5 kG The magnetic field strength of a sunspot
100 tesla 1 T to 2.4 T 10 kG to 24 kG Coil gap of a typical loudspeaker magnet.[7]
1 T to 2 T 10 kG to 20 kG Inside the core of a modern 50/60 Hz power transformer[8][9]
1.25 T 12.5 kG Strength of a modern neodymium–iron–boron (Nd2Fe14B) rare earth magnet. A coin-sized neodymium magnet can lift more than 9 kg, erase credit cards.[10]
1.5 T to 7 T 15 kG to 30 kG Strength of medical magnetic resonance imaging systems in practice, experimentally up to 11.7 T[11][12][13]
9.4 T 94 kG Modern high resolution research magnetic resonance imaging system; field strength of a 400 MHz NMR spectrometer
101 decatesla 11.7 T 117 kG Field strength of a 500 MHz NMR spectrometer
16 T 160 kG Strength used to levitate a frog[14]
23.5 T 235 kG Field strength of a 1 GHz NMR spectrometer[15]
38 T 380 kG Strongest continuous magnetic field produced by non-superconductive resistive magnet.[16]
45 T 450 kG Strongest continuous magnetic field yet produced in a laboratory (Florida State University's National High Magnetic Field Laboratory in Tallahassee, USA).[17]
102 hectotesla  100 T 1 MG Strongest pulsed non-destructive magnetic field produced in a laboratory, Pulsed Field Facility at National High Magnetic Field Laboratory's, Los Alamos National Laboratory, Los Alamos, NM, USA).[18]
103 kilotesla 1 kT 10 MG Strongest (pulsed) magnetic field ever obtained in a laboratory (Z machine, Sandia National Laboratories in Albuquerque, New Mexico)[19]
106 megatesla 1 MT to 100 MT 10 GG to 1 TG Strength of a neutron star
108 - 1011 gigatesla 100 MT to 100 GT 1 TG to 1 PG Strength of a magnetar
1053 N/A 2×1029 YT 2×1033 YG Planck magnetic field strength

## References

1. ^ "Bureau International des Poids et Mesures, The International System of Units (SI), 8th edition 2006" (PDF). bipm.org. 2012-10-01. Retrieved 2013-05-26.
2. ^ [1] Gravity Probe B
3. ^ "Surprises from the Edge of the Solar System". NASA. 2006-09-21.
4. ^ a b c "Magnetic Field Levels Around Homes" (PDF). UC San Diego Dept. of Environment, Health & Safety (EH&S). p. 2. Retrieved 2017-03-07.
5. ^ a b "EMF in Your Environment: Magnetic Field Measurements of Everyday Electrical Devices". United States Environmental Protection Agency. 1992. pp. 23–24. Retrieved 2017-03-07.
6. ^ "Information on MRI Technique". Nevus Network. Retrieved 2014-01-28.
7. ^ Elliot, Rod. "Power Handling Vs. Efficiency". Retrieved 2008-02-17.
8. ^ "Inductors and transformers" (PDF). eece.ksu.edu. 2003-08-12. Archived from the original (PDF) on September 8, 2008. Retrieved 2013-05-26. A modern well-designed 60 Hz power transformer will probably have a magnetic flux density between 1 and 2 T inside the core.
9. ^ "Trafo-Bestimmung 3von3". radiomuseum.org. 2009-07-11. Retrieved 2013-06-01.
10. ^ The Tesla Radio Conspiracy
11. ^ Savage, Niel. "The World's Most Powerful MRI Takes Shape".
12. ^ Smith, Hans-Jørgen. "Magnetic resonance imaging". Medcyclopaedia Textbook of Radiology. GE Healthcare. Archived from the original on 2012-02-07. Retrieved 2007-03-26.
13. ^ Orenstein, Beth W. (2006-02-16). "Ultra High-Field MRI — The Pull of Big Magnets". Radiology Today. 7 (3). p. 10. Archived from the original on March 15, 2008. Retrieved 2008-07-10.
14. ^
15. ^
16. ^
17. ^
18. ^
19. ^ "Z machine makes progress toward nuclear fusion". October 10, 2014. Retrieved August 10, 2016.