Magnetic Declination Calculator Compass True North

Magnetic Declination Formula:

\[ \text{True} = \text{Magnetic} + \text{Declination} \]

True Heading:

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1. What is Magnetic Declination?

Magnetic declination is the angle between magnetic north (the direction the compass points) and true north (the direction along Earth's surface towards the geographic North Pole). This angle varies depending on your location on Earth and changes over time.

2. How Does the Calculator Work?

The calculator uses the magnetic declination formula:

\[ \text{True Heading} = \text{Magnetic Heading} + \text{Declination} \]

Where:

Magnetic Heading — The compass reading in degrees
Declination — The angular difference between true north and magnetic north for your location (positive for east, negative for west)
True Heading — The corrected heading relative to true north

Explanation: The formula adjusts your compass reading to account for the local difference between magnetic and true north.

3. Importance of Magnetic Declination

Details: Correcting for declination is essential for accurate navigation, especially in wilderness areas, aviation, and marine navigation where small angular errors can lead to significant positional errors over long distances.

4. Using the Calculator

Tips: Enter your compass reading (0-360 degrees) and the local magnetic declination (positive for east, negative for west). The calculator will give you the true heading adjusted for declination.

5. Frequently Asked Questions (FAQ)

Q1: How do I find my local magnetic declination?
A: Use NOAA's online calculator, topographic maps (which show declination), or mobile apps that provide current declination data.

Q2: Does declination change over time?
A: Yes, magnetic north moves gradually, so declination values should be updated every few years for precise navigation.

Q3: What's the difference between east and west declination?
A: East declination means magnetic north is east of true north (add declination), west means it's west of true north (subtract declination).

Q4: How significant is declination for navigation?
A: Even a few degrees can matter over long distances. At 60 miles, 1° error equals about 1 mile off course.

Q5: Can I set my compass to account for declination?
A: Many quality compasses have adjustable declination settings to automatically correct readings.