The oersted is a unit of magnetic field strength in the emu system. The magnetic field produced at the center of a plane circular induction coil of one turn and a radius of one centimeter, which carries a current of 1/2π amperes.

The unit is named after Hans Christian Ørsted who discovered electromagnetism in 1820.


Oersted is also name of the first Danish satellite, which was successfully launched into space on February 23, 1999. The main scientific objective of the spacecraft was to map the Earth's magnetic field.