Convert from millimeter to block [East U.S.]

Unit Definition (millimeter)
The millimeter (or millimetre) is one of the most common metric units of distance. One millimeter is exactly one thousandth of a meter. The millimeter is also an engineering standard unit.

Unit Definition (block [East U.S.])
The Block is an informal unit of distance popular in the U.S. A block is the average distance between street intersections in the rectangular street grids common in most American cities. The length of a block in Eastern USA is about 1/20 mile or 80 meters.