In the form below there are three groups of fields. Each group has several fields followed by a help icon. When the help icon is selected, it will insert information about the group below the group of fields.
This calculator may be used to calculate values of all seven magnetic components: D, I, H, Z, F, X, Y. The International Geomagnetic Reference Field is used to compute values within Canada and elsewhere in the world.
Tips and more information about this calculator.
Magnetic reference field models give results that are typically accurate to about 150 nT, but the difference between the model value and the true value of the magnetic field at a given location is dependent on a number of factors. As the time from the epoch of the model increases, uncertainties in the estimate of secular variation will result in an increasingly large difference. Magnetic minerals in local geological formations cause magnetic anomalies that can sometimes reach thousands of nanoteslas. These cannot be reproduced by reference field models. Finally, large magnetic storms can temporarily cause large changes in the magnetic field, especially at high latitudes.
See also the magnetic declination calculator.