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International Geomagnetic Reference Field (IGRF), 13th Generation 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 International Geomagnetic Reference Field (IGRF), 13th Generation, as released in Dec 2019.

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/igrf/13/?latitude=-80&longitude=240&altitude=0&date=2022-07-02&format=xml modifying the query string parameters as appropriate.

Geodetic Coordinates
(See note 1)
(See note 1)
km above MSL
D = Declination I = Inclination X = North Intensity Y = East Intensity H = Horizontal Intensity Z = Vertical Intensity F = Total Intensity
MF = Main Field degrees east degrees down nT nT nT nT down nT
SV = Secular Variation arcmin/year arcmin/year nT/year nT/year nT/year nT/year nT/year

Please note that for Internet Explorer 10 and earlier there may be occasional erratic behaviour from the clickable map and the pop-up window. For very old versions of Internet Explorer the results may not be visible.