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Brief description of geomagnetism and observation systems

About WMM

Learn more about model derivation, uncertainties and magnetic poles

Model & Software

Download model coefficients, software and documentation

Online Calculators

Calculate magnetic field values at or near the Earth surface


Browse imagery and contour maps for main field and secular change

Uses of WMM

Common applications of WMM


License and copyright information

National Geospatial-Intelligence Agency.

This website is being retired. Please check out our new website here https://www.ncei.noaa.gov/products/world-magnetic-model

The World Magnetic Model

The World Magnetic Model is a joint product of the United States’ National Geospatial-Intelligence Agency (NGA) and the United Kingdom’s Defence Geographic Centre (DGC). The WMM was developed jointly by the National Centers for Environmental Information (NCEI, Boulder CO, USA) (formerly National Geophysical Data Center (NGDC)) and the British Geological Survey (BGS, Edinburgh, Scotland).

The World Magnetic Model is the standard model used by the U.S. Department of Defense, the U.K. Ministry of Defence, the North Atlantic Treaty Organization (NATO) and the International Hydrographic Organization (IHO), for navigation, attitude and heading referencing systems using the geomagnetic field. It is also used widely in civilian navigation and heading systems. The model, associated software, and documentation are distributed by NCEI on behalf of NGA. The model is produced at 5-year intervals, with the current model expiring on December 31, 2024.

World Magnetic Model News

12/16/2021: State of the Geomagnetic Field Report Released

The December 2021 State of the Geomagnetic Field report is now available. This report provides an assessment of the performance of the WMM2020 two years after its release, and describes noteworthy changes in the Earth's main magnetic field, including magnetic pole drifts and the deepening of the South Atlantic Anomaly.

12/10/2019: WMM2020 Release

The full release of the WMM (WMM2020) is now available. All WMM products and services have been updated.

8/1/2019: World Magnetic Model 2020 Release Date Announced

As part of the regular update cycle of the World Magnetic Model, NCEI, in collaboration with the British Geological Survey will release the WMM2020 on December 10, 2019.

3/20/2019: MagQuest Challenge Launched

The National Geospatial-Intelligence Agency (NGA) launched a $1.2M challenge to advance geomagnetic data collection for the World Magnetic Model. More information can be found on the MagQuest Website.

2/28/2019: New WMM Mil-Spec Released

The National Geospatial-Intelligence Agency (NGA) has released a new military specification document, MIL-PRF-89500B, for the World Magnetic Model. This document updates the error requirements for WMM and is now available.

Please contact geomag.models@noaa.gov for comments or questions.

WMM 2020 Declination Map

WMM2020 Declination Map

WMM 2020 Total Intensity Map

WMM2020 Total Intensity Map

Last Modified on: Tuesday, 10-Jan-2023 17:59:14 UTC
NOAA > NESDIS > NCEI (formerly NGDC)
Maintained by: geomag.models@noaa.gov