How do I determine runway designations from magnetic heading?

Round the runway's magnetic azimuth to the nearest 10 degrees and drop the trailing zero, so a 174-degree heading becomes Runway 17. The reciprocal end is numbered 180 degrees opposite, Runway 35. AvPlot derives both ends from the magnetic heading using NASR magnetic variation.

Why don't runway numbers match the true heading?

Runway numbers are based on magnetic north, not true north. Because magnetic variation drifts over time, runways are occasionally renumbered, which is why a runway's designation can change without the pavement moving.

What do the L, C, and R suffixes on a runway mean?

For parallel runways, L (left), C (center), and R (right) distinguish runways that share the same magnetic heading number.

AvPlot — Runway Designation Calculator

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Runway Designation Calculator

Compute parallel runway designators and magnetic variation adjustments per FAA standards.

Runway Designation Calculator

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Airport Magnetic Variation (Optional)

Runway designations are based on magnetic north. Enter your airport to look up the published magnetic variation, or enter the variation manually.

Airport Identifier

FAA LID or ICAO. A 3-letter code is read as US ICAO (DEN → KDEN).

Magnetic Variation

Negative = West Positive = East

Magnetic Heading → Runway Number

Magnetic Heading degrees

Runway Number → Heading Range

Find the range of headings that correspond to a given runway number.

Runway Number

ⓘ Runway designations are based on magnetic north. As magnetic declination changes over time, runway designations may be updated by the FAA. Always verify against the current FAA Chart Supplement and active NOTAMs before use in official documents.