The centimeter (cm) is a metric unit of length equal to one-hundredth of a meter, commonly used for everyday measurements around the world. It appears on rulers, in clothing sizes, and in medical records for body measurements. One centimeter is equivalent to approximately 0.3937 inches, providing a convenient scale between millimeters and meters.

The inch (in) is an imperial unit of length equal to exactly 25.4 millimeters, widely used in the United States, Canada, and the United Kingdom. It is the standard measurement for screen sizes, pipe diameters, and mechanical fasteners, and remains common in everyday use across North America. One inch equals exactly 2.54 centimeters.