Convert from feet [survey] to em

Unit Definition (feet [survey])
A foot (plural: feet) is a non-SI unit of distance or length, measuring around a third of a metre. There are twelve inches in one foot and three feet in one yard.

Unit Definition (em)
The em is a printer's unit of relative distance. One em is the height of the type size (in points) being used. If 12 point type is being set, then one em is 12 points, and so on.