When utilising the metric system of measurements, it is possible to convert inches to millimetres by using simple mathematical calculations and procedures. The metric system is stated in increments of 10, which is significant since it makes calculating the distance between metres, centimetres, and millimetres simple. Using a precise multiplication factor, you may quickly convert inch to mm.

If you are using a measuring tape or ruler to measure the distance, multiply it by the value of 25.4 to convert the measurement into millimetres.

In to Mm Formula & Examples

As established, 1 inch = 25.4 mm. In light of this, the conversion formula would be to multiply the number of inches by 25.4 to find the units of millimetres. 

Let’s understand this formula with the help of examples.

Example 1

Convert 15 inch to millimetre

Hence, 15inch to mm would be : 15 X 25.4 = 381mm

Example 2 

Convert 16 inch to mm

Hence, 16 inches to mm would be: 16 X 25.4 = 406.4mm

What is an Inch(in)?

The British Imperial and American customary measurement systems both contributed to the development of the inch as a unit of length measurement. In some measurement systems, the word inch has been designated as the intermediate conversion unit. It is derived from the term “Roman uncia,” which means “twelfth.” This can also be inferred from the thumb’s breadth in humans. It’s also interesting to note that the conventional meaning of “inch” has changed over time, and the unit’s precise value has occasionally varied. However, since the 1960s, when the worldwide yard system was adopted, the value was eventually based on the metric system, and it is now precisely 25.4mm. 

  • Current Use of Inches

In the United States, Canada, and even the United Kingdom, the “inch” is commonly used as a unit of measurement. An inch is used for the measurement of electrical parts and display panels across much of continental Europe. Even in Japan, this unit of measurement is widely used.

As for the United Kingdom, the inch has been the primary unit of measurement alongside the foot since October 1, 1995. Although, inches were frequently employed for distance-related sizes like road signs. A double prime serves as the worldwide standard symbol’s indication (denoted by double quotes). However, a single prime is used to symbolise the foot (characterised by an apostrophe). Three feet and two inches, for instance, can be expressed as 3’2″. This is similar to how the degree’s first and second cuts employ the prime and double prime symbols.

  • History of Inches

The earliest reference of inch has been known to emerge from England. The Laws of Æthelberht, which date from the early 7th century, are where we get this remembrance of an inch. The Textus Roffensis, dating from 1120, mentions a variety of depths, including one inch, two inches, one shilling, and two shillings.

The Imperial Standard Yard was used to define an inch in the United Kingdom and the majority of other British Commonwealth nations. The measuring factor was later adopted by the United States of America in 1866 to define an inch. Thus, 1 metre was defined as 39.37 inches. As a result, the inch is now written as 25.4000508 mm (reference temperature of 68 degrees Fahrenheit).

What is a Millimetre(mm)?

In the metric system, a millimetre is a unit of measurement equal to one thousandth of a metre. Since the metre is the SI unit of measurement, being expressed in terms of it makes it more practical. Therefore,

10mm = 1cm

1000mm = 1m

1mm = 1000 micrometres

1mm = 1000000 nanometres

1 inch = 25.4 mm (which is approximately 0.03937 of an inch)

  • Current Use of mm(millimetre)

A millimetre is the smallest unit of measurement in the metric system. For the same purpose, there are digital callipers (measuring tools) that can read a measurement as fine as 0.01 mm. 

The millimetre unit is largely employed in the metric system and can be used to measure anything from wavelengths to paper and hair.

    • The wavelength and frequency of a microwave are 1 mm and 300 GHz, respectively.
    • Up to 0.02 to 0.04 mm can be used to measure the smallest unit of distance.
    • From gauging the thickness of a human hair to papers as thin as 0.07mm and 0.18mm.
  • History of Millimetre

The origins of the metric system can be traced to the Age of Enlightenment, when multiples and fractions, as well as lengths and widths, were measured in nature. The unit of measurement extended throughout France and Europe in less than 50 years. The system also included other metrics with unity ratios, which were later used all across the world. The metric system first became apparent in 1799, during the French Revolution. The metric system began to be widely adopted as a unit of measurement.

James Clerk Maxwell optimised a coherent system in the middle of the 19th century in which there could be a single base unit from which other units would eventually be derived. These units would be referred to as “derived units.” Maxwell proposed three fundamental units for length, mass, and time. The 19th century saw advancements in electromagnetism, including the addition of new units to make the systems more comprehensible and adaptable to the current measurement system.

Later it was concluded that an integrated system of measurement requiring electromagnetic units needed an electromagnetism base unit. As a result, millimetres are frequently used as the principal measurement unit across numerous sectors.

Relation Between Inch To Mm

Inches are prominently used in the imperial system of measurement. On the other hand, the metric system of measurement includes millimetres. It should be noted that 1 inch = 25.4 mm is the typical ratio between the two.

By calculating the relationship between these units, we can quickly convert between the two. There are a number of ways to make straightforward translations if you are familiar with the metric system of measurements. The standard ratio of 1 inch to 10 millimetres is 25.4. The same foundation can be used for all subsequent calculations.

Abbreviations Commonly Used To Represent ‘inch’ and ‘Mm’

Inch is usually denoted by ‘in’ and millimetre is usually marked by ‘mm’ in the metric system and the imperial systems of measurement. 

Inch To Mm Conversion Table

Let us take a look at the inch to millimetre conversion table to understand the formula better. This table will serve as an inch to mm calculator to ease the conversion process. 

Inch MM Inch to Millimetres
1 inches 25.4 mm 1 inches to mm = 25.4 mm
2 inches 50.8 mm 2 inches to mm = 50.8 mm
3 inches 76.2 mm 3 inches to mm = 76.2 mm
4 inches 101.6 mm 4 inches to mm = 101.6 mm
5 inches 127 mm 5 inches to mm = 127 mm
6 inches 152.4 mm 6 inches to mm = 152.4 mm
7 inches 177.8 mm 7 inches to mm = 177.8 mm
8 inches 203.2 mm 8 inches to mm = 203.2 mm
9 inches 228.6 mm 9 inches to mm = 228.6 mm
10 inches 254 mm 10 inches to mm = 254 mm
11 inches 279.4 mm 11 inches to mm = 279.4 mm
12 inches 304.8 mm 12 inches to mm = 304.8 mm
13 inches 330.2 mm 13 inches to mm = 330.2 mm
14 inches 355.6 mm 14 inches to mm = 355.6 mm
15 inches 381 mm 15 inches to mm = 381 mm
16 inches 406.4 mm 16 inches to mm = 406.4 mm
17 inches 431.8 mm 17 inches to mm = 431.8 mm
18 inches 457.2 mm 18 inches to mm = 457.2 mm
19 inches 482.6 mm 19 inches to mm = 482.6 mm
20 inches 508 mm 20 inches to mm = 508 mm
21 inches 533.4 mm 21 inches to mm = 533.4 mm
22 inches 558.8 mm 22 inches to mm = 558.8 mm
23 inches 584.2 mm 23 inches to mm = 584.2 mm
24 inches 609.6 mm 24 inches to mm = 609.6 mm
25 inches 635 mm 25 inches to mm = 635 mm
26 inches 660.4 mm 26 inches to mm = 660.4 mm
27 inches 685.8 mm 27 inches to mm = 685.8 mm
28 inches 711.2 mm 28 inches to mm = 711.2 mm
29 inches 736.6 mm 29 inches to mm = 736.6 mm
30 inches 762 mm 30 inches to mm = 762 mm
31 inches 787.4 mm 31 inches to mm = 787.4 mm
32 inches 812.8 mm 32 inches to mm = 812.8 mm
33 inches 838.2 mm 33 inches to mm = 838.2 mm
34 inches 863.6 mm 34 inches to mm = 863.6 mm
35 inches 889 mm 35 inches to mm = 889 mm
36 inches 914.4 mm 36 inches to mm = 914.4 mm
37 inches 939.8 mm 37 inches to mm = 939.8 mm
38 inches 965.2 mm 38 inches to mm = 965.2 mm
39 inches 990.6 mm 39 inches to mm = 990.6 mm
40 inches 1016 mm 40 inches to mm = 1016 mm
41 inches 1041.4 mm 41 inches to mm = 1041.4 mm
42 inches 1066.8 mm 42 inches to mm = 1066.8 mm
43 inches 1092.2 mm 43 inches to mm = 1092.2 mm
44 inches 1117.6 mm 44 inches to mm = 1117.6 mm
45 inches 1143 mm 45 inches to mm = 1143 mm
46 inches 1168.4 mm 46 inches to mm = 1168.4 mm
47 inches 1193.8 mm 47 inches to mm = 1193.8 mm
48 inches 1219.2 mm 48 inches to mm = 1219.2 mm
49 inches 1244.6 mm 49 inches to mm = 1244.6 mm
50 inches 1270 mm 50 inches to mm = 1270 mm

Difference Between Inch(in) and Millimetre(mm)

The fundamental distinction is that millimetres is used within the metric system of measuring whereas inches is used in the imperial system. We can convert inches to millimetres by establishing a common ground as both units of measurement are employed in a variety of industry standards. 

Frequently Asked Question (FAQs)

What size is 1 inch in mm?

1 inch is equal to 25.4 mm upon inch to millimetre conversion.

What is the scale of 1 inch to yards?

1 inch is equal to 0.027777 yards.

What size is 8 inches in mm?

If we convert inch to mm then 8 inches will be equal to 203.2 mm.