Magnetic Declination

Magnetic declination, sometimes called magnetic variation, is the angle between magnetic north and true north. Declination is considered positive east of true north and negative when west.

As illustrated in the graph to the left, magnetic declination changes over time and with location.

If you would like to learn more about magnetic declination and Earth's changing magnetic field, we recommend visiting NGDC's Answers to Frequently Asked Questions.

• Compute your declination based on the International Geomagnetic Reference Field Model, version 10 (1900-2010)
• Compute the historic (pre-1900) declination for the conterminous U.S.
• Compute all seven magnetic field parameters based on the IGRF (1900 - 2010)
  
• View maps of declination for the Conterminous USA (2004), Alaska (2000), Hawaii (2000), and the World (2005 - pdf 641Kb)
• View or download Declination map suitable for printing (pdf):
  • Conterminous U.S. 8 x 11(2Mb)
  • Conterminous U.S. 11 x 17 (3.5Mb) page size
  • Alaska (2000) (4.6 Mb),
  • Hawaii (2000), (2.7 Mb) and