Inches and centimeters both units of length. The inch ( in ) is a British imperial unit defined as 1⁄12th of a foot. The centimeter ( cm ) is 1⁄100th of the standard meter. They can be converted using a conversion factor of
1 inch = 2.54 centimeters.
These two worked example problems show how to convert from inches to centimeters and centimeters to inches.
Convert Inches to Centimeters Example Problem
Question: A six-foot-tall person is 72 inches tall. How many centimeters tall is a six-foot person?
Solution: Set up the conversion factor so the undesired unit is in the denominator. In this case, we want inches to cancel out. To see why this works, check out How to Convert Units – Ladder Method.
72 in = 72 in
Note how the inches unit cancels out, leaving only the centimeter unit.
72 in = 72 · 2.54 cm
72 in = 182.88 cm
Answer: A six-foot-tall person is 182.88 centimeters tall.
Convert Centimeters to Inches Example Problem
Question: The near point of the human eye is the shortest distance the eye can naturally focus on an object. This value is defined to be 25 centimeters. How many inches is the human eye near point?
Solution: Like before, set up the conversion factor so the undesired unit will in the denominator. This time, centimeters should go in the denominator.
25 cm = 9.8 inches
Answer: The human eye near point is 9.8 inches.
The conversion between inches and centimeters is one of the conversion factors I recommend you memorize if you are a budding engineer. Inches have a long history in engineering applications and tend to pop up in nearly every standard. Just remember the 2.54 number and an inch is bigger than a centimeter.