Magnetic declination/magnetic variation is the angle between magnetic north and true north at a particular location on the Earth’s surface.
Our maps do not show the magnetic declination. The angle can change over time due to polar wandering. To obtain the current declination value of a location, we recommend using available magnetic declination calculators. Please note that local geological conditions can cause larger deviations from the values given:
Germany
https://isdc.gfz-potsdam.de/igrf-declination-calculator/
Austria
https://www.zamg.ac.at/cms/de/geophysik/produkte-und-services-1/online-deklinationsrechner
Worldwide
https://www.ngdc.noaa.gov/geomag/calculators/magcalc.shtml#declination