Enter the true bearing and the magnetic bearing into the calculator to determine the magnetic declination. This calculator helps in finding the difference between the true north and magnetic north.
Magnetic Declination Formula
The following formula is used to calculate the magnetic declination:
D = MB - TB
Variables:
- D is the magnetic declination (degrees)
- MB is the magnetic bearing (degrees)
- TB is the true bearing (degrees)
To calculate the magnetic declination, subtract the true bearing from the magnetic bearing.
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.
How to Calculate Magnetic Declination?
The following steps outline how to calculate the Magnetic Declination:
- First, determine the true bearing (TB) in degrees.
- Next, determine the magnetic bearing (MB) in degrees.
- Use the formula D = MB – TB to calculate the magnetic declination (D).
- Finally, enter the values into the calculator to check your result.
Example Problem:
Use the following variables as an example problem to test your knowledge.
True Bearing (TB) = 120 degrees
Magnetic Bearing (MB) = 115 degrees