Inches (in) to Millimeters (mm) Converter

This length unit converter dynamically calculates a value you enter in inches (in) and converts it to its equivalent value in millimeters (mm).

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How many inches (in) are in a millimeter (mm)? What is the formula for how to convert inches to millimeters (in to mm)?

1 inch (in) = 25.4 millimeters (mm)
So we can say that there is 25.4 millimeters in 1 inch.
This means that the multiplication conversion factor to convert a quantity expressed in an inch unit of measurement to an equivalent quantity expressed in a millimeter unit of measurement is 25.4.

Inversely (or reciprocally),

1 millimeter (mm) = 0.039370078740157 inch (in)
So we can say that there is 0.039370078740157 inch in 1 millimeter.
This means that the division conversion factor to convert a quantity expressed in an inch unit of measurement to an equivalent quantity expressed in a millimeter unit of measurement is 0.039370078740157.

Knowing this inverse mathematical relationship between the two conversion factors and their reciprocal operations, we can derive two formulas to calculate and convert a quantity of length expressed in inches to an equivalent quantity of length expressed in millimeters (in to mm). Both formulas will yield the same result. The formulas are:

mm = in × 25.4    → This is the formula based on the multiplication conversion factor.

and

mm = in ÷ 0.039370078740157    → This is the formula based on the division conversion factor.

For example, if you have a length of 8 inches that you want to convert to millimeters, you would use either of the two formulas as follows:

mm = 8 in × 25.4 = 203.2 mm
mm = 8 in ÷ 0.039370078740157 = 203.2 mm

So, the result is the same using either formula, which is 203.2 millimeters.

Inches to millimeters (in to mm) conversion chart

To save you time and effort spent on having to perform manual calculations or look up conversion formulas every time a conversion from inches to millimeters is needed, here is a inches-to-millimeters conversion chart for your quick and easy reference. This conversion chart (or conversion table) shows common measurement values of length in inches and their equivalent measurement values in millimeters. These equivalent measurement values may be rounded off to 1 or 2 decimal places when it is mathematically expedient for everyday applications.

inches (in)millimeters (mm)
1 in25.4 mm
2 in50.8 mm
3 in76.2 mm
4 in101.6 mm
5 in127.0 mm
6 in152.4 mm
7 in177.8 mm
8 in203.2 mm
9 in228.6 mm
10 in254.0 mm
11 in279.4 mm
12 in304.8 mm
13 in330.2 mm
14 in355.6 mm
15 in381.0 mm
16 in406.4 mm
17 in431.8 mm
18 in457.2 mm
19 in482.6 mm
20 in508.0 mm
21 in533.4 mm
22 in558.8 mm
23 in584.2 mm
24 in609.6 mm
25 in635.0 mm
26 in660.4 mm
27 in685.8 mm
28 in711.2 mm
29 in736.6 mm
30 in762.0 mm
31 in787.4 mm
32 in812.8 mm
33 in838.2 mm
34 in863.6 mm
35 in889.0 mm
36 in914.4 mm
37 in939.8 mm
38 in965.2 mm
39 in990.6 mm
40 in1,016.0 mm
41 in1,041.4 mm
42 in1,066.8 mm
43 in1,092.2 mm
44 in1,117.6 mm
45 in1,143.0 mm
46 in1,168.4 mm
47 in1,193.8 mm
48 in1,219.2 mm
49 in1,244.6 mm
50 in1,270.0 mm
51 in1,295.4 mm
52 in1,320.8 mm
53 in1,346.2 mm
54 in1,371.6 mm
55 in1,397.0 mm
56 in1,422.4 mm
57 in1,447.8 mm
58 in1,473.2 mm
59 in1,498.6 mm
60 in1,524.0 mm
61 in1,549.4 mm
62 in1,574.8 mm
63 in1,600.2 mm
64 in1,625.6 mm
65 in1,651.0 mm
66 in1,676.4 mm
67 in1,701.8 mm
68 in1,727.2 mm
69 in1,752.6 mm
70 in1,778.0 mm
71 in1,803.4 mm
72 in1,828.8 mm
73 in1,854.2 mm
74 in1,879.6 mm
75 in1,905.0 mm
76 in1,930.4 mm
77 in1,955.8 mm
78 in1,981.2 mm
79 in2,006.6 mm
80 in2,032.0 mm
81 in2,057.4 mm
82 in2,082.8 mm
83 in2,108.2 mm
84 in2,133.6 mm
85 in2,159.0 mm
86 in2,184.4 mm
87 in2,209.8 mm
88 in2,235.2 mm
89 in2,260.6 mm
90 in2,286.0 mm
91 in2,311.4 mm
92 in2,336.8 mm
93 in2,362.2 mm
94 in2,387.6 mm
95 in2,413.0 mm
96 in2,438.4 mm
97 in2,463.8 mm
98 in2,489.2 mm
99 in2,514.6 mm
100 in2,540.0 mm
inches (in)millimeters (mm)
101 in2,565.4 mm
102 in2,590.8 mm
103 in2,616.2 mm
104 in2,641.6 mm
105 in2,667.0 mm
106 in2,692.4 mm
107 in2,717.8 mm
108 in2,743.2 mm
109 in2,768.6 mm
110 in2,794.0 mm
111 in2,819.4 mm
112 in2,844.8 mm
113 in2,870.2 mm
114 in2,895.6 mm
115 in2,921.0 mm
116 in2,946.4 mm
117 in2,971.8 mm
118 in2,997.2 mm
119 in3,022.6 mm
120 in3,048.0 mm
121 in3,073.4 mm
122 in3,098.8 mm
123 in3,124.2 mm
124 in3,149.6 mm
125 in3,175.0 mm
126 in3,200.4 mm
127 in3,225.8 mm
128 in3,251.2 mm
129 in3,276.6 mm
130 in3,302.0 mm
131 in3,327.4 mm
132 in3,352.8 mm
133 in3,378.2 mm
134 in3,403.6 mm
135 in3,429.0 mm
136 in3,454.4 mm
137 in3,479.8 mm
138 in3,505.2 mm
139 in3,530.6 mm
140 in3,556.0 mm
141 in3,581.4 mm
142 in3,606.8 mm
143 in3,632.2 mm
144 in3,657.6 mm
145 in3,683.0 mm
146 in3,708.4 mm
147 in3,733.8 mm
148 in3,759.2 mm
149 in3,784.6 mm
150 in3,810.0 mm
151 in3,835.4 mm
152 in3,860.8 mm
153 in3,886.2 mm
154 in3,911.6 mm
155 in3,937.0 mm
156 in3,962.4 mm
157 in3,987.8 mm
158 in4,013.2 mm
159 in4,038.6 mm
160 in4,064.0 mm
161 in4,089.4 mm
162 in4,114.8 mm
163 in4,140.2 mm
164 in4,165.6 mm
165 in4,191.0 mm
166 in4,216.4 mm
167 in4,241.8 mm
168 in4,267.2 mm
169 in4,292.6 mm
170 in4,318.0 mm
171 in4,343.4 mm
172 in4,368.8 mm
173 in4,394.2 mm
174 in4,419.6 mm
175 in4,445.0 mm
176 in4,470.4 mm
177 in4,495.8 mm
178 in4,521.2 mm
179 in4,546.6 mm
180 in4,572.0 mm
181 in4,597.4 mm
182 in4,622.8 mm
183 in4,648.2 mm
184 in4,673.6 mm
185 in4,699.0 mm
186 in4,724.4 mm
187 in4,749.8 mm
188 in4,775.2 mm
189 in4,800.6 mm
190 in4,826.0 mm
191 in4,851.4 mm
192 in4,876.8 mm
193 in4,902.2 mm
194 in4,927.6 mm
195 in4,953.0 mm
196 in4,978.4 mm
197 in5,003.8 mm
198 in5,029.2 mm
199 in5,054.6 mm
200 in5,080.0 mm

Conversion of 1 inch (in) to other units of length

Here is a reference list providing a conversion of 1 inch (in) to its equivalent values in various units of length, both metric and imperial:

  • 1 inch (in) = 25,400,000 nanometers (nm)
  • 1 inch (in) = 25,400 micrometers (µm)
  • 1 inch (in) = 25.4 millimeters (mm)
  • 1 inch (in) = 2.54 centimeters (cm)
  • 1 inch (in) = 0.254 decimeter (dm)
  • 1 inch (in) = 0.0254 meter (m)
  • 1 inch (in) = 0.0000254 kilometer (km)
  • 1 inch (in) = 0.083333333333333 feet (ft)
  • 1 inch (in) = 0.027777777777778 yard (yd)
  • 1 inch (in) = 0.000015782828282828 mile (mi)
  • 1 inch (in) = 0.000013714902807775 nautical mile (nmi)

What is an inch (in)?

Definition of inch: An inch is an imperial and US customary unit of length equal to 1/12 of a foot or 2.54 centimeters. It is often used in the United States and the United Kingdom, that follow these measurement systems for small measurements such as in construction and carpentry.

The abbreviation for inch is in. The single Unicode character ㏌ (U+33CC) represents the 2-character Latin abbreviation for inch. The Windows Alt code for this character ㏌ is Alt + 13260.

The informal symbol for inch is represented by a double prime (″) or double quote (“). For example, 12 inches can be written as 12″.

What is a millimeter (mm)?

Definition of millimeter: A millimeter is a unit of length in the International System of Units (SI). It is equivalent to one thousandth of a meter (10^-3 m). It is commonly used for precisely measuring small lengths and dimensions such as mechanical parts in engineering and manufacturing.

The abbreviation for millimeter is mm. The single Unicode character ㎜ (U+339C) represents the 2-character Latin abbreviation for millimeter. The Windows Alt code for this character ㎜ is Alt + 13212.