Aerial View Of Airport Runway

Runways are given a number between 01 and 36. This indicates the runway's heading: A runway with the number 36 points to the north (360°), runway 09 points east (90°), runway 18 is south (180°), and runway 27 points west (270°). Thus, the runway number is one tenth of the runway centerline's magnetic azimuth, measured clockwise from the magnetic declination.
A runway can normally be used in two directions, which means the runway may have two names: "runway 33" and "runway 15". The two numbers always differ by 18 (= 180°).