The rectangular field of play used for American football games measures long between the goal lines, and (53.3 yards) wide. The field may be made of grass or artificial turf. In addition, there are end zones extending another past the goal lines to the "end lines", for a total length of . When the "football field" is used as unit of measurement, it is usually understood to mean , although technically the full length of the official field, including the end zones, is . The total area of the field is . There is a goal centered on each end line, with a crossbar above the ground and goalposts apart extending at least above the crossbar. Between the goal lines, additional lines span the width of the field at 5-yard intervals. This appearance led to the use of the term gridiron in the 1880s. For a few years in the early 20th century, lines perpendicular to the lines at 5-yard intervals spanned the length of the field, giving it a checkerboard-like appearance.
This article mainly describes the field used in the National Football League, college football, and other leagues playing (traditionally) outdoor 11-man football. Other variants of American football such as nine-man or arena football typically use smaller fields with smaller end zones.
Field description
The entire field is a rectangle long by wide; covering a total of 1.32 acres. The longer lines are the sidelines and the shorter lines are called end lines. NFL rules call for the sidelines and end lines to be wide, though the lines may be narrower on fields used for multiple sports or by college or amateur teams. In all cases the sidelines and end lines are measured along the inside edges of the boundary lines, and the lines themselves are out of bounds. Most distances on a football field are expressed in terms of yards.
The goal lines span the width of the field and run parallel to each end line. The 100 yards between the goal lines where most gameplay occurs is officially called the field of play in the NFL rulebook. Additional lines span the width of the field at 5-yard intervals from each goal line.
End zones
The areas at each end of the field between the goal lines and end lines – including the goal lines themselves – are called the end zones. The end zones are where touchdowns, two-point conversions, and safeties are scored, and where touchbacks occur. Orange weighted pylons mark the four corners of each end zone. Team or league logos or other patterns may be painted inside the end zone as long as they do not interfere with the mandatory field markings.
Goals
A goal is centered on each end line, consisting of a horizontal crossbar above the ground and aligned with the inside edge of the end line, with vertical goal posts (colloquially "uprights") at each end of the crossbar apart and extending at least above the crossbar. The goals are where field goals (including rare fair catch kicks) and extra points after touchdowns are scored. All NFL fields and many collegiate and amateur fields have slingshot-shaped goal structures, with a single gooseneck-shaped support post anchored to the ground out of bounds. Other amateur fields, particularly at the high school level, may have H-shaped goal structures with two support posts anchored to the ground directly below the crossbar; on fields used for multiple sports these goals may double as soccer goals at the appropriate regulation width for that sport, along with the goal structure behind it and netting. The NFL requires a ribbon to be attached to the top of each goal post to indicate wind direction and speed. Goal posts must be yellow in the NFL unless waived due to extraordinary circumstances; collegiate fields may have yellow or white goal posts. Amateur fields may also have shorter goal posts or a wider space between the goal posts. Since 1974, NFL rules has the goalposts positioned at the end line; prior to that season, they were on the goal line (the college game has had them at the end line since 1927).
Yard lines
A yard line refers to the distance of some point on the 100-yard field of play – usually the line of scrimmage or the spot where a play ends – from the nearest goal line. When moving away from one goal line, the yard line numbers increase from 1 to 50 (midfield), then decrease back to 1 approaching the opposite goal line. Each yard line is said to "belong" to the team defending the closer end zone; for example, during a period where Team A is defending the north end zone and Team B is defending the south end zone, the 25-yard line closer to the north end zone is said to be Team A's 25-yard line.