Millimeters
The most appropriate unit to measure a pencil would be centimeters or inches. These units are commonly used for measuring small objects like pencils due to their size. A standard pencil is typically around 17.5 centimeters or 6.9 inches long.
Length: meter Mass: kilogram Volume: cubic meter
If units are in centimeters cubed, you would use a ruler or a measuring tape to measure the length, width, and height of an object in centimeters. You can then multiply these three dimensions together to calculate the volume in cubic centimeters.
Pencil lead is very narrow. Millimeter can be used to measure it.
to be honest I would use a metre ruler that really helps a lot place your metre ruler on your desk. put your pencil starting from 0. Then measure it. This is how you would measure it.