Magnetic Declination Calculator

Written by Great Medico

Updated September 25, 2026 •2 min read

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A magnetic declination result can look convincing even when one unit or assumption is off. Electrical and magnetic results can shift sharply with geometry, frequency, phase, material properties, and whether the quantity is a magnitude or signed value. This page keeps the calculation narrow enough to trace the answer back to the values you enter.

What this calculator does

The Magnetic Declination Calculator connects Latitude, Longitude, Elevation to the page’s magnetic declination. Supporting values are included only when they follow from the same relationship, so you can compare the headline with the quantities behind it.

How to use it

Enter Latitude, Longitude, Elevation, Date using the units shown beside each field. Set ºN/ºS, ºE/ºW to match the solve path you want. Keep all values from the same physical case, then check the headline result and any supporting values before changing one input at a time for comparison.

How the calculation works

Magnetic declination is normally the angular difference between true and magnetic north and requires a geomagnetic field model when it is predicted from latitude, longitude, altitude, and date. The current form does not run such a model from those visible inputs.

Example

The default location fields currently return 0° rather than a date-specific geomagnetic prediction. Do not interpret that as evidence that declination is actually zero at the entered latitude and longitude; a proper example requires a geomagnetic model such as WMM/IGRF, which this page is not currently running.

How to interpret the result

Read the magnetic declination with its sign, magnitude, phase, frequency, geometry, and unit as applicable. A field, reactance, power factor, loss, or flux value should be compared only with a quantity defined in the same way.

Limitations and notes

Latitude, longitude, elevation, hemisphere, and date are visible, but the current calculation does not run a geomagnetic reference model from them. Its fallback declination relationship expects true and magnetic bearings that this form does not provide. A displayed 0° should therefore not be treated as local magnetic declination.