The World Magnetic Model (WMM) is the standard model for navigation, attitude, and heading referencing systems that use the geomagnetic field. The WMM is also used for civilian applications, including navigation and heading systems.
A new version of the model is updated every five years to address changes in Earth’s magnetic field. The current version (WMM2025) was released on December 17, 2024, and will remain valid until late 2029.
The World Magnetic Model High Resolution (WMMHR) is an advanced geomagnetic field model that provides a more detailed, accurate depiction of the geomagnetic field than the World Magnetic Model (WMM). WMMHR2025 includes core field and secular variation coefficients for degrees n = 1 to 15. This model also covers the crustal field (from n=16 through n=133). As a result, it has more coefficients ((18,210 non-zero coefficients instead of 336) and more digits (4 instead of 1) in each coefficient.
The WMM and WMMHR models were sponsored by the United States’ National Geospatial-Intelligence Agency (NGA) and the United Kingdom’s Defence Geographic Centre (DGC). NOAA National Centers for Environmental Information (NCEI) and the British Geological Survey (BGS) jointly developed the WMM and WMMHR
WMM2025 Coefficient File [+ CIRES link]
WMMHR2025 Coefficient File [+ CIRES link]
Citations
Models Values
NOAA NCEI Geomagnetic Modeling Team; British Geological Survey. 2024: World Magnetic Model 2025. NOAA National Centers for Environmental Information. https://doi.org/10.25921/aqfd-sd83. Accessed [date].
NOAA NCEI Geomagnetic Modeling Team; British Geological Survey. 2024: World Magnetic Model High Resolution 2025. NOAA National Centers for Environmental Information. https://doi.org/10.25921/qb1c-vn52. Accessed [date].
Technical Report
Chulliat, A., W. Brown, P. Alken, C. Beggan, M. Nair, G. Cox, A. Woods, S. Macmillan, B. Meyer and M. Paniccia, The US/UK World Magnetic Model for 2020-2025: Technical Report, National Centers for Environmental Information, NOAA, https://10.25923/ytk1-yx35, 2020.
Note: The WMM source code is in the public domain and not licensed or under copyright. The information and software may be used freely by the public. As required by 17 U.S.C. 403, third parties producing copyrighted works consisting predominantly of the material produced by U.S. government agencies must provide notice with such work(s) identifying the U.S. Government material incorporated and stating that such material is not subject to copyright protection.