Metres.
The meter.
Officials use yards, as a football field is 100 yards.
Meters would be the standard SI (Système international)unit for measuring something the general length of a football field.
Yards
Usually, you would use kilometers.
Metres, to measure its length or width, square metres to measure its area.
Length would be the most appropriate unit of measurement
a big tape measure thing, I think they are used for construction, but I don't know the exact name for them
use inches
Decimeter
A tape measure.