VOR Radial to Heading Calculator

Enter your true course, magnetic variation, compass deviation, and distance to instantly calculate magnetic heading, compass heading, intercept heading, holding outbound time, and ILS altitude loss.

Created by Luis GonzalezLast updated: May 9, 2026

How to Use This Calculator

1
Enter True Course (°)
Input the intended true course (track) for your flight segment in degrees, as measured from true north on an aeronautical chart.
2
Provide Magnetic Variation (°)
Enter the magnetic variation for your geographic location. Use a negative value for West variation and a positive value for East variation.
3
Input Compass Deviation (°)
Enter the compass deviation from your aircraft's compass correction card. This corrects for magnetic interference within the aircraft.
4
Specify Distance (NM)
Input the distance to the VOR station or fix in nautical miles. This affects holding pattern outbound time calculations.
5
Review Headings and Aviation Metrics
Examine the calculated magnetic heading, compass heading, intercept heading, and holding pattern times, crucial for instrument flight.

Example Calculation

A pilot plans a true course of 215° to a VOR station 125 NM away. The magnetic variation is 6° West (-6°), and the compass deviation is 2° East (+2°). They need to determine the magnetic and compass headings.

True Course (°)

215

Magnetic Variation (°)

-6

Compass Deviation (°)

Distance (NM)

125

Results

221.0°

Tips

Remember 'East is Least, West is Best'

When converting True Course to Magnetic Course, remember the adage: 'East is Least (subtract East variation), West is Best (add West variation)'. For this calculator, West variation is entered as negative, so `True Course - (-West Variation)` becomes `True Course + West Variation`.

Always Consult Your Compass Card

Compass deviation is unique to each aircraft and even varies with heading. Regularly check your aircraft's compass correction card, typically mounted near the compass, for the most accurate deviation values for your current heading.

Understand the 30° Intercept Rule

The 30° intercept heading is a common practice for intercepting a VOR radial or course, allowing for a gradual and controlled turn onto the desired track. This value can be adjusted based on wind conditions or desired intercept angle.

The VOR Radial to Heading Calculator is an indispensable tool for pilots, aviation students, and flight planners, simplifying complex navigation calculations. It converts true course into magnetic and compass headings by accounting for magnetic variation and compass deviation, crucial for accurate instrument flight. Additionally, it provides insights into intercept headings and holding pattern parameters. This precision is vital for maintaining safe and efficient flight paths, especially during instrument meteorological conditions (IMC), where a deviation of even a few degrees can lead to significant navigational errors over long distances.

Navigating VOR Radials in Airspace

For pilots operating under Instrument Flight Rules (IFR), accurately navigating VOR (VHF Omnidirectional Range) radials is a fundamental skill. VOR stations are ground-based electronic navigation aids that transmit signals, allowing an aircraft's VOR receiver to determine its bearing relative to the station. This calculator helps convert the true course (from a chart) into the magnetic heading required to fly a specific VOR radial, and then further into the compass heading accounting for aircraft-specific magnetic interference. For instance, when flying a 215° true course, a pilot might need to fly a 221° magnetic heading due to local magnetic variation, and a 219° compass heading due to aircraft deviation. Precision in these conversions is critical to stay within designated airspace, avoid obstacles, and execute instrument approach procedures safely.

The Aviation Formulas for Course and Heading Conversion

Converting between true course, magnetic heading, and compass heading involves applying specific corrections for magnetic variation and compass deviation. The core formulas are:

True Course to Magnetic Heading: Magnetic Heading = True Course - Magnetic Variation (Remember: West Variation is negative, East Variation is positive. So, True Course - (-West Var) becomes True Course + West Var).
Magnetic Heading to Compass Heading: Compass Heading = Magnetic Heading - Compass Deviation

These calculations adjust the desired ground track (True Course) to what the aircraft's magnetic compass will display (Compass Heading), enabling the pilot to fly the correct path. The normalize function ensures angles remain between 0 and 360 degrees.

💡 Since magnetic variation is a critical input here, if you need to determine its value for a specific location and time, our Magnetic Variation Calculator can provide that data.

Plotting a VOR Radial Intercept: A Pilot's Example

Consider a pilot planning an instrument flight. Their true course to a VOR station is 215°. At their current position, the magnetic variation is 6° West (input as -6°), and the aircraft's compass correction card indicates a deviation of 2° East (input as 2°) for this heading. The VOR station is 125 nautical miles away.

Calculate Magnetic Heading: Magnetic Heading = True Course - Magnetic Variation Magnetic Heading = 215° - (-6°) Magnetic Heading = 215° + 6° = 221°
Calculate Compass Heading: Compass Heading = Magnetic Heading - Compass Deviation Compass Heading = 221° - 2° = 219°
Calculate Intercept Heading (standard 30°): Intercept Heading = Compass Heading + 30° Intercept Heading = 219° + 30° = 249°
Determine Holding Outbound Time: For distances over 14 NM, standard is 1.5 minutes. Holding Outbound Time = 1.5 min
Calculate Total Altitude Loss (ILS Glide Slope): Total Altitude Loss = 318 ft/NM × 125 NM = 39,750 ft

The pilot will fly a magnetic heading of 221° and a compass heading of 219° to maintain the desired course.

💡 Accurate navigation is crucial for all phases of flight. After determining your course, you might need to calculate the space required for your approach. Our Landing Distance Calculator helps assess runway requirements.

In aviation, adherence to specific benchmarks for headings and navigation parameters is non-negotiable for safety and regulatory compliance.

Magnetic Variation: Varies geographically from 0° (agonic line) to over 20° East or West, significantly impacting magnetic headings. Pilots must use current sectional charts or electronic flight bags (EFBs) for values within 1-2 degrees of accuracy.
Compass Deviation: Typically kept to a minimum, ideally within ±3° on any heading, as per FAA standards. A deviation beyond this range necessitates a compass swing by a qualified technician.
Intercept Angles: Standard practice for VOR or GPS course intercepts is often 30° for en route segments, but can be adjusted to 45° or even 90° depending on controller instructions or specific approach procedures.
Holding Pattern Times: FAA regulations specify a 1-minute outbound leg for holding patterns at or below 14,000 feet Mean Sea Level (MSL), and a 1.5-minute outbound leg above 14,000 feet MSL.
ILS Glide Slope: The standard Instrument Landing System (ILS) glide slope is 3°, which corresponds to approximately 318 feet of altitude loss per nautical mile. Deviations from this precise rate can lead to unstable approaches. These benchmarks are critical for pilots to maintain positional awareness and execute maneuvers safely and efficiently within the National Airspace System.

Frequently Asked Questions

What is the difference between true course, magnetic heading, and compass heading?

True course is the intended path over the ground measured relative to true north, found on aeronautical charts. Magnetic heading is the direction the aircraft's nose is pointed relative to magnetic north, which differs from true north due to magnetic variation. Compass heading is the reading on the aircraft's magnetic compass, which further deviates from magnetic heading due to local magnetic interference from the aircraft's electrical systems, known as compass deviation.

How does magnetic variation affect navigation?

Magnetic variation is the angular difference between true north and magnetic north at a specific location on Earth. It significantly affects navigation because aeronautical charts use true north, while aircraft magnetic compasses point to magnetic north. Pilots must apply magnetic variation to convert true courses from charts into magnetic headings for use with their onboard magnetic compass and VOR instruments, ensuring they fly the correct ground track.

What is compass deviation and why does it occur?

Compass deviation is the error in a magnetic compass reading caused by local magnetic fields within the aircraft itself. These fields are generated by electrical currents, ferrous metals, and other components. Deviation varies with the aircraft's heading and must be accounted for by referring to a compass correction card, which lists the necessary corrections for various magnetic headings. Regular compass swings are performed to update this card.

What is a VOR radial?

A VOR (VHF Omnidirectional Range) radial is a line of position extending outwards from a VOR ground station. VOR stations transmit signals that allow aircraft to determine their bearing relative to the station, providing 360 radial courses. Pilots use VOR radials for en route navigation, holding patterns, and instrument approaches. The VOR receiver in the aircraft indicates which radial the aircraft is on or which radial it is flying to or from.