An effective scale conversion calculator is available at the Bureau of Economic Geology website, where the calculator converts to both metric and imperial units. Alternatively, a great scale conversion calculator can be found at the Scale Models website.
Map scales proportion the distance on the ground with a representative distance on a map. For example, a map scale of 1:100,000 means that one unit on the map is the equivalent to a section on the ground 100,000 units long. Map scales can be increased or decreased, in that 0.1:100,000 is the equivalent scale of 1:1,000,000. These representative scales are unit-less.