World Magnetic Model 2015 Calculator

Use the tool below to compute values for the geomagnetic field and secular variation for a given set of coordinates and date. This calculator uses the World Magnetic Model.

Choose the geodetic latitude and longitude either by entering the coordinates into the form below (decimal degrees may be entered into the 'degrees' field, and degrees S or W should be entered with a negative sign), or by simply clicking the location on the map. The altitude and date may be set using the appropriate form fields.

Clicking on the 'Show result on map' button will display the values for the chosen coordinates in a pop-up window. These results may be saved by clicking on the 'Save' button allowing you to compare values from a number of locations.

As this is based on a web service you can also obtain results in XML format using an HTTP GET request http://geomag.bgs.ac.uk/web_service/GMModels/wmm/2015?latitude=-80&longitude=240&altitude=0&date=2017-07-02&format=xml, modifying the query string parameters as appropriate.