Magnetic Declination Calculator

Formula

The formula to calculate the magnetic declination is:

\[ D = MB - TB \]

Where:

\( D \) is the magnetic declination (degrees)
\( MB \) is the magnetic bearing (degrees)
\( TB \) is the true bearing (degrees)

What is Magnetic Declination?

Magnetic declination, also known as magnetic variation, is the angle on the horizontal plane between magnetic north (the direction the north end of a compass needle points) and true north (the direction along the Earth’s surface towards the geographic North Pole). This angle varies depending on position on the Earth’s surface and changes over time.

Example Calculation

Let's assume the following values:

Magnetic Bearing (MB) = 350 degrees
True Bearing (TB) = 360 degrees

Using the formula:

\[ D = 350 - 360 = -10 \, \text{degrees} \]

The magnetic declination (D) is -10 degrees.