Convert from football field [U.S.] to feet [international, U.S.]

Unit Definition (football field [U.S.])
The football field is a common informal unit of distance in the United States and Canada. Americans aren't quite agreed as to whether the unit is exactly 100 yards (91.44 meters), the distance between the goal lines on an American football field, or 120 yards (109.728 meters), the distance including the two end zones. Canadian football fields are 110 yards (100.58 meters) long between the goal lines and 150 yards (137.16 meters) including the end zones. The football field is also used sometimes as an informal unit of area: including the end zones, an American football field represents an area of 1.3223 acre or about 0.535 hectare while the Canadian football field has an area of 2.0145 acre or 0.815 hectare.

Unit Definition (feet [international, U.S.])
The human foot has long been a standard unit for the measurement of length. Over history this size has varied from region to region and there is some discrepancy as to an exact standard or origin of the standard measurement for feet that we use today. In England, the Roman foot was replaced after the fall of Rome by the natural foot. The modern foot (1/3 yard or about 30.48 centimeters) did not appear until after the Norman conquest of 1066. It may be an innovation of Henry I, who reigned from 1100 to 1135. Later in the 1100's a foot of modern length, the "foot of St. Paul's," was inscribed on the base of a column of St. Paul's Church in London.