The ISO length unit to use would be the cementer.
Centimeters.
foot
Foot
Metre or foot and inches
foot is the most precise way to measure any unit
the units that are used to measure a foot are meters and inches.
A square unit is a measure of area, a foot is a linear unit. There are no area units in any linear measure.
Vertical Foot
Square Foot
meter
A foot.
If you live in the United States, you should use inches. If you live outside of the US, you should use centimetres.