Millimeters-Inches Converter
Enter the length in either of the next two fields and get it converted instantly from mm to inches or the opposite, from inches to mm. Inches are printed both in decimal and fraction form.
Millimeters [mm]: | |||
Inches [in]: | |||
 Inches can be decimal or fractional. For example: 5.5 or 5 1/2 | |||
Fraction [in]: | |||
Decimal [in]: | |||
Feet-Inches: | |||
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Conversion Formulas
1 inch = 25.4 mm
1 mm ≈ 0.03937
Rule of thumb:
100 mm ≈ 4 inches
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Definitions
Table of contents
Unit of millimeter
The millimeter or millimetre [mm] is a unit of length from the SI system of units. It is defined as one thousandth (1/1000) of the meter. The meter [m], is the base unit of length in SI system, and is currently established as the distance traveled by light in vacuum in seconds.
Common multiple and fraction units of the metre are defined through the decimal SI prefixes, as presented in the following table:
| Unit | Symbol | [m] |
|---|---|---|
| Nanometer | nm | 10-9 |
| Micrometer | μm | 10-6 |
| Millimeter | mm | 0.001 |
| Centimeter | cm | 0.01 |
| Hectometer | hm | 100 |
| Kilometer | km | 1000 |
| Megameter | Mm | 106 |
Unit of inch
Inch [in] is a unit of length in the Imperial and US customary system of units. It was historically conceived as the length of 3 barley-corns. Today, it is defined through the meter SI unit as: 1 in = 0.0254 m (= 2.54 cm = 25.4 mm).
Multiple units of the inch are defined as shown in the table:
| Unit | Symbol | [in] |
|---|---|---|
| Foot | ft | 12 |
| Yard | yd | 36 |
| Mile | mi | 63360 |
How to convert inches to mm
- Multiply distance in [in] with 25.4
- The result is the distance in mm
For example, to convert 1/2 inches to mm, do: mm
How to convert mm to inches
- Divide distance in [mm] by 25.4
- The result is the distance in inches
For example, to convert 150 mm to inches, do: inches
Conversion chart - inches to mm
The following chart can be used to convert from inches to mm. A typical cell in the table gives the conversion in cm for X Y/Z inches, defined as:
- X (whole inches) given in the 1st cell of the row
- Y/Z (fractional part) given in column head
| inch to mm | |||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 0 | 1/16" | 1/8" | 3/16" | 1/4" | 5/16" | 3/8" | 7/16" | 1/2" | 9/16" | 5/8" | 11/16" | 3/4" | 13/16" | 7/8" | 15/16" | ||
| 0" | 0 | 1.59 | 3.17 | 4.76 | 6.35 | 7.94 | 9.52 | 11.1 | 12.7 | 14.3 | 15.9 | 17.5 | 19 | 20.6 | 22.2 | 23.8 | 0" |
| 1" | 25.4 | 27 | 28.6 | 30.2 | 31.8 | 33.3 | 34.9 | 36.5 | 38.1 | 39.7 | 41.3 | 42.9 | 44.4 | 46 | 47.6 | 49.2 | 1" |
| 2" | 50.8 | 52.4 | 54 | 55.6 | 57.1 | 58.7 | 60.3 | 61.9 | 63.5 | 65.1 | 66.7 | 68.3 | 69.8 | 71.4 | 73 | 74.6 | 2" |
| 3" | 76.2 | 77.8 | 79.4 | 81 | 82.5 | 84.1 | 85.7 | 87.3 | 88.9 | 90.5 | 92.1 | 93.7 | 95.3 | 96.8 | 98.4 | 100 | 3" |
| 4" | 102 | 103 | 105 | 106 | 108 | 110 | 111 | 113 | 114 | 116 | 117 | 119 | 121 | 122 | 124 | 125 | 4" |
| 5" | 127 | 129 | 130 | 132 | 133 | 135 | 137 | 138 | 140 | 141 | 143 | 144 | 146 | 148 | 149 | 151 | 5" |
| 6" | 152 | 154 | 156 | 157 | 159 | 160 | 162 | 164 | 165 | 167 | 168 | 170 | 171 | 173 | 175 | 176 | 6" |
| 7" | 178 | 179 | 181 | 183 | 184 | 186 | 187 | 189 | 191 | 192 | 194 | 195 | 197 | 198 | 200 | 202 | 7" |
| 8" | 203 | 205 | 206 | 208 | 210 | 211 | 213 | 214 | 216 | 217 | 219 | 221 | 222 | 224 | 225 | 227 | 8" |
| 9" | 229 | 230 | 232 | 233 | 235 | 237 | 238 | 240 | 241 | 243 | 244 | 246 | 248 | 249 | 251 | 252 | 9" |
| 10" | 254 | 256 | 257 | 259 | 260 | 262 | 264 | 265 | 267 | 268 | 270 | 271 | 273 | 275 | 276 | 278 | 10" |
| 11" | 279 | 281 | 283 | 284 | 286 | 287 | 289 | 291 | 292 | 294 | 295 | 297 | 298 | 300 | 302 | 303 | 11" |
| 12" | 305 | 306 | 308 | 310 | 311 | 313 | 314 | 316 | 318 | 319 | 321 | 322 | 324 | 325 | 327 | 329 | 12" |
| 0 | 1/16" | 1/8" | 3/16" | 1/4" | 5/16" | 3/8" | 7/16" | 1/2" | 9/16" | 5/8" | 11/16" | 3/4" | 13/16" | 7/8" | 15/16" | ||
| 1inch = 25.4mm **** 100 mm ≈ 4 in | |||||||||||||||||
How to use the above chart
Let's say that we want to convert 5 3/8 inches to cm. First we select 5 whole inches by the respective row in the chart (row starting with 5"). Then, we look for the column having 3/8 at its head. The selected cell has a value of 137. Therefore, we conclude that 5 3/8 inches are equal to 137mm.
Conversion table from mm to inches
In the following table some typical distances in millimeters are converted to inches:
| [mm] | [in] |
|---|---|
| 0.5 | 0.01969 |
| 1 | 0.03937 |
| 2 | 0.07874 |
| 3 | 0.1181 |
| 5 | 0.1969 |
| 10 | 0.3937 |
| 12 | 0.4724 |
| 20 | 0.7874 |
| 30 | 1.181 |
| 40 | 1.575 |
| 50 | 1.969 |
| 100 | 3.937 |
| 200 | 7.874 |
| 300 | 11.81 |
| 400 | 15.75 |
| 500 | 19.69 |
| 600 | 23.62 |
| 700 | 27.56 |
| 800 | 31.5 |
| 900 | 35.43 |
| 1000 | 39.37 |
Conversion table from inches to mm
In the following table some typical distances in inches are converted to millimeters:
| [in] | [mm] |
|---|---|
| 0.125 | 3.175 |
| 0.25 | 6.35 |
| 0.375 | 9.525 |
| 0.5 | 12.7 |
| 1 | 25.4 |
| 2 | 50.8 |
| 3 | 76.2 |
| 5 | 127 |
| 10 | 254 |
| 12 | 304.8 |
| 20 | 508 |
| 30 | 762 |
| 50 | 1270 |