Magnetic Declination Calculator, Formula and Sample Sums

Magnetic Declination Calculator :

Enter the Magnetic declination  calculator its Latitude in °N, Longitude in °W, Elevation in kilometers(km), and get the calculation below the calculator check it.

Magnetic Declination Calculator

Magnetic Declination Formula :

  • From the Declination Calculator: The declination calculator is a simple tool for determining the declination of any location on the globe. The calculator calculates the declination using magnetic reference field models by entering the year, degree, and longitude of a specific region.
  • From the Declination Chart: A magnetic declination chart is a tool for calculating declination. The magnetic fields of the world are depicted on the chart. Finding magnetic declination is made simple using this method.
  • From the Compass: True, magnetic, and compass bearings are the three types of bearing available.

T = M + V

M = C + D

T = C + V + D (which is a general equation relating compass and true bearings)


C →Compass Bearing

M → Magnetic Bearing

T → True Bearing

V→ Variation

D →Compass Deviation

Sample Sums :

Sum1 :

Where the horizontal and vertical components of the earth’s magnetic field are identical, what is the angle of dip?

Solution :

Angle of dip is,

δ = tan-1(BV/BH)


BV = The magnetic field’s vertical components,

BH = The magnetic field’s horizontal components.

Therefore, BV = BH

δ = tan-1(1)

= 45o.

Sum2 :

The North point of a magnetic needle free to rotate in a vertical plane parallel to the magnetic meridian has a 60° angle to the horizontal. The earth’s magnetic field has a horizontal component of 1.2 G at this location. Calculate the magnitude of the earth’s magnetic field at your location.

Solution :

Given: δ = 60o, H = 1.2 G


Be = H / cos δ

Be = 1.2 / cos 60

= 1.2 / (0.5)

= 2.4 G.

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