To convert 1.8 inch to millimeter, multiply the inch value by the conversion factor 25.400000. So, 1.8 multiplied by 25.400000 equals 45.7200 millimeter.

1.8 inch equals exactly 45.720000 millimeter. For practical purposes, this is often rounded to 45.7200 millimeter.

Objects measuring approximately 1.8 inch include the length of a Hershey's Miniatures candy bar (1.75 inch), the diameter of a McCormick standard spice jar (1.75 inch), or the width of an Apple Watch SE 44mm case (1.73 inch).

Converting inch to millimeter is useful for ensuring compatibility in international manufacturing and engineering, adhering to global metric standards, and facilitating precise measurements in scientific and technical applications where metric is the primary system.

A simple memory aid is to remember that 1 inch is roughly 2 and a half centimeters, or 25.4 millimeters. For 1.8 inch, you can estimate it as 'almost 2 inches', which would be just under 50.8 mm. Visualizing objects like a single-serve condiment packet can also serve as a quick reference.