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# Mm to Inches Converter

## How to convert Mm to Inches?

Converting millimeters to inches is straightforward. To do this, multiply the value in millimeters by 0.039. For instance, to change 30 mm into inches, perform the following calculation:

30 mm equals 30 × 0.039, which is 1.17 inches.

Suppose you possess a ruler that is 25 mm long. To determine its length in inches:

25 mm in inches is 25 × 0.039, totaling 0.975 inches.

For precise measurements, objects are often measured in millimeters. Consider a lens that is 500 mm long. To translate this measurement to inches:

500 mm in inches is 500 × 0.039, which equals 19.5 inches.

## MM to Inches Formula and Example

The formula to convert millimeters to inches is straightforward and can be expressed as follows:

Inches = MM X 0.0393701

Here are some examples of converting millimeters to inches:

MM Inches
10 0.3937
20 0.7874
30 1.1811
40 1.5748
50 1.9685
60 2.3622
70 2.7559
80 3.1496
90 3.5433
100 3.937

## Convert Mm to Inches Online

Make quick and accurate length conversions by entering millimeters and obtaining inches in an instant with our online tool. Enter any number in millimeters, and our tool will automatically convert it to inches for you. Below is a default value; you should change it to your desired number.

mm
3.937 Inches
(rounded to 4 digits)

(Note: 1 inch = 25.4 mm)

### How many inches in a millimeter

One millimeter is equal to 0.03937 inches:

1mm = 1mm / 25.4mm/in = 0.03937in

### How many millimeters in an inch

One inch is equal to 25.4 millimeters:

1in = 25.4mm/in × 1in = 25.4mm

## mm to Inches Conversion Chart

Millimeters Inches (decimal) Inches (fraction)
1 mm 0.03937″ 3/64″
2 mm 0.07874″ 5/64″
3 mm 0.11811″ 1/8″
4 mm 0.15748″ 5/32″
5 mm 0.19685″ 13/64″
6 mm 0.23622″ 15/64″
7 mm 0.275591″ 9/32″
8 mm 0.314961″ 5/16″
9 mm 0.354331″ 23/64″
10 mm 0.393701″ 25/64″
11 mm 0.433071″ 7/16″
12 mm 0.472441″ 15/32″
13 mm 0.511811″ 33/64″
14 mm 0.551181″ 35/64″
15 mm 0.590551″ 19/32″
16 mm 0.629921″ 5/8″
17 mm 0.669291″ 43/64″
18 mm 0.708661″ 45/64″
19 mm 0.748031″ 3/4″
20 mm 0.787402″ 25/32″
21 mm 0.826772″ 53/64″
22 mm 0.866142″ 55/64″
23 mm 0.905512″ 29/32″
24 mm 0.944882″ 15/16″
25 mm 0.984252″ 63/64″
26 mm 1.0236″ 1 1/32″
27 mm 1.063″ 1 1/16″
28 mm 1.1024″ 1 7/64″
29 mm 1.1417″ 1 9/64″
30 mm 1.1811″ 1 3/16″
31 mm 1.2205″ 1 7/32″
32 mm 1.2598″ 1 17/64″
33 mm 1.2992″ 1 19/64″
34 mm 1.3386″ 1 11/32″
35 mm 1.378″ 1 3/8″
36 mm 1.4173″ 1 27/64″
37 mm 1.4567″ 1 29/64″
38 mm 1.4961″ 1 1/2″
39 mm 1.5354″ 1 17/32″
40 mm 1.5748″ 1 37/64″

Definition: A millimeter, denoted as mm, constitutes a unit of length within the International System of Units (SI). It is precisely defined as 1/1000th of a meter, which corresponds to the distance that light travels in 1/299,792,458,000 of a second.

History/origin: The “milli-” prefix is one of numerous metric prefixes, signifying a division by one thousand of the base unit, the meter, in this instance. Although the definition of the meter has undergone modifications over time, the relationship between the meter and the millimeter remains constant. Previously, the meter was defined based on the length of a prototype meter bar. However, in 2019, the meter was redefined to align with changes made to the definition of a second.

Definition: An inch, represented as “in,” serves as a unit of length in the imperial and US customary systems of measurement. The inch was officially determined to be precisely equal to 25.4 millimeters in 1959. There are 12 inches in a foot and 36 inches in a yard.

History/origin: The term “inch” derives from the Latin word “uncia,” which equated to “one-twelfth” of a Roman foot.

Throughout history, various standards for the inch have existed, with the contemporary definition being based on the international yard. One of the earliest definitions of the inch was based on the length of barleycorns, where an inch corresponded to the length of three grains of dry, round barley arranged end-to-end. Another iteration of the inch is believed to have been derived from the width of a human thumb, calculated as an average of three thumb widths: a small, medium, and large thumb.

Current use: The inch is primarily utilized in the United States, Canada, and the United Kingdom. It is also occasionally employed in Japan, along with other countries, particularly in the context of electronic components, such as display screen sizes.

### Difference between Mm and Inches

Here’s a table summarizing the differences between millimeters (mm) and inches (in):

Aspect Millimeters (mm) Inches (in)
Definition 1 mm = 1/1000th of a meter 1 in = 1/12th of a foot
1 mm ≈ 0.03937 inches 1 in = 25.4 mm
Smaller Units 1 millimeter is smaller 1 inch is larger
Larger Units 1 meter = 1000 millimeters 1 foot = 12 inches
Conversion Factor 1 millimeter ≈ 0.03937 inches 1 inch ≈ 25.4 millimeters
Use Common in the metric system Common in the imperial system
Used globally for precision Commonly used in the US, UK,
measurements and engineering and for some electronics sizes
(e.g., screen dimensions)

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