When you are using scales on a drawing, do not
confuse the engineers scale with a metric scale. They
are very similar in appearance. You will often find
metric dimensions used on blueprints from other
countries. Metric drawings are dimensioned in
millimeters (mm). There are 25.4 millimeters to an
inch. A meter is 39.37 inches, a few inches longer than
a yard measure.
Scales of 1:100 and 1:200 are common scales for
metric drawings. One millimeter on the drawing
represents 100 or 200 millimeters on the actual
Metric blueprints developed in the United States
are normally marked METRIC. In countries that
use metric, however, no metric notations are made.