Inches and centimetres are two units to measure length. On a smaller scale, for example, to measure a pencil’s length, we use inches in the United States and centimetres in the rest of the world. They sound alike in scale; however, 1 inch is equivalent to 2.54 centimetres. If you need to make a very quick estimate of how many centimetres make a certain length in inches, you would be actually multiplying the number of inches by 2.5. This method is appropriate for making a rough estimate of the length without the use of a calculator.

As, we already know that an inch is longer than a centimetre, therefore, if you are in a puzzling situation of whether to multiply or divide by 2.5, try one of the operations and verify. If there are more centimetres in the result for the value given in inches, it’s wrong.

Let us understand how to convert inches to centimetres with the help of an example.

If you are asked to convert 20 inches to centimetres and if you get the result as

cm, you can confirm it to be the wrong answer because the value in centimetres is less than the value in inches. Due to the reason that an inch is always longer than a centimetre, it takes more centimetres to form the same length in inches. So we need to multiply 2.5 by the given inches to get the right answer as 10 inches.

inches.

Before we learn the relation between the two common units of linear measurements which are inches and centimetres, we need to know what they are.

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Inch Definition

In mathematics, the customary system, which is actually the system used in the United States, is available for measuring the set of length, weight, capacity, and temperature. It is based on the English measurement system. The customary system consists of units like inches, cups, gallons, etc. These are often called imperial measures.

An inch can be defined as the customary system unit of length of measurement. It is represented by the symbol, ``. It is most often denoted by “in”.

For example, 18 inches is represented as 18`` or 18 in.

There are 2 half inches and 4 quarter inches in one whole inch.

The inch representation is as follows

One inch = 1 in

One half of an inch = in

One-quarter of an inch = in

One-eighth of an inch = in

One-sixteenth of an inch = in.

in is the smallest unit on a ruler.

Centimetre Definition

In the metric system that most parts of the world use, a centimeter is a unit for measuring length. It is denoted by “cm”. 100 centimetres make one meter. 10 millimetres make one centimetre. A centimetre is about one-third the size of an inch.

In short,

1 centimetre = meter = 10 millimeters = 0.3937 inches.

Inch and centimetre are related such that one inch, in the customary system, is equal to 2.54 cms in the metric system.

1`` = 2.54 cm

In other words, the measurement given in centimetres is equal to the measurement given in inches times 2.54 centimetres.

Convert Inches to Centimeters Example Problem

Question: An eight-foot-tall person is 96 inches tall. How many centimetres tall is an eight-foot person?

The conversion factor which is 2.54 inches, needed to be set up in such a way that the undesired unit comes in the denominator. In this case, we want the inches to cancel out

96 in = 96in

The first step is to multiply 96in with a fraction containing the numerator 2.54 cm and denominator 1in.

Now, we will be cancelling out the inches unit and leaving behind the centimetre unit alone as follows:

Hence we obtain the result in centimetres by multiplying 96 with the value 2.54. This will give us 243.84 cm.

96 in = 243.84 cm

Answer: The eight-foot-tall person is 243.88 centimetres tall.

The conversion between inches and centimetres is one of the very important conversion factors that any budding engineer will need to know. Inches have a long history in the applications that especially prevails in the field of engineering. As a result of this, inches tend to pop up in almost every standard. Just make sure you remember the fact that an inch is bigger than a centimetre and the value 2.54.

By being aware of such conversions, we can make sure that people globally have the ability to communicate the different measurements for different quantities in the most effective manner.