Convert length units instantly — meters, feet, inches, centimeters, kilometers, miles, and more.
| Unit | Name | Value |
|---|---|---|
| m | Meter | 0.001 |
| km | Kilometer | 0.000001 |
| cm | Centimeter | 0.1 |
| in | Inch | 0.039370079 |
| ft | Foot | 0.0032808399 |
| yd | Yard | 0.0010936133 |
| mi | Mile | 6.2137119e-7 |
| nmi | Nautical Mile | 5.399568e-7 |
Multiply the number of Millimeters by 0.0393701 to get Inchs. Formula: in = mm × 0.0393701. Example: 10 mm × 0.0393701 = 0.393701 in. To reverse, divide Inchs by 0.0393701 to get Millimeters.
| Millimeter (mm) | Inch (in) |
|---|---|
| 0.001 mm | 3.93701e-05 in |
| 0.01 mm | 0.000393701 in |
| 0.1 mm | 0.00393701 in |
| 0.5 mm | 0.019685 in |
| 1 mm | 0.0393701 in |
| 2 mm | 0.0787402 in |
| 5 mm | 0.19685 in |
| 10 mm | 0.393701 in |
| 20 mm | 0.787402 in |
| 50 mm | 1.9685 in |
| 100 mm | 3.93701 in |
| 250 mm | 9.84252 in |
| 500 mm | 19.685 in |
| 1000 mm | 39.3701 in |
| 10000 mm | 393.701 in |
To convert Millimeter to Inch, multiply by 0.0393701. Example: 10 mm = 0.393701 in
To convert Inch back to Millimeter, divide by 0.0393701 (multiply by 25.4). Use the swap button above.
Start with 100 Millimeters = 3.93701 in as your reference point. Scale up or down from there.
1 inch = 25.4 mm exactly — the most important cross-system engineering conversion. Every global manufacturer, engineer, or machinist working between metric and US customary performs mm-to-inch conversion multiple times daily.
Metric bolts use mm for diameter (M8 = 8mm) while US fasteners use fractional inches. Engineers and buyers selecting fasteners routinely convert between mm and inches for every hardware specification and cross-reference.
EU medical devices specified in mm must be converted to inches for US FDA submissions. Every medical device sold in both markets has dual mm and inch specifications — the conversion underpins global device market access.
Display pixel pitch is specified in mm during manufacturing while consumer screen sizes use diagonal inches. Every display product converts between mm panel dimensions and inch screen sizes for global product listings.
Metric pipe systems use mm for nominal diameter (DN50 = 50mm OD) while US piping uses inches. Every cross-border infrastructure project requires mm-to-inch conversion for pipe specification and fitting compatibility.
Professional printing uses mm for margins, bleed, and trim dimensions while US publication sizes use inches (8.5×11", A4 in mm). Every international print job converts between mm and inch specifications for consistent output.
The Millimeter is a unit of Length measurement (symbol: mm). 1 mm = 0.0393701 in. Used in scientific and practical Length measurement applications.
The Inch is a unit of Length measurement (symbol: in). It is part of an internationally recognised measurement system used alongside the Millimeter.
The millimetre was introduced alongside the metre in 1795 as part of the French metric system — one-thousandth of a metre, from the Latin 'mille' (thousand). Its practical importance emerged during the Industrial Revolution, when manufacturing tolerances first needed sub-centimetre precision. By the 20th century, ISO engineering drawing standards adopted millimetres as the primary dimension unit for all technical drawings worldwide. Today millimetres are the universal language of engineering — from the finest watch gear to the largest aircraft fuselage — and are the most widely used length unit in global manufacturing.
The inch has one of the most colourful origin stories in measurement history. An English statute from 1324 under King Edward II defined it as 'three grains of barley, dry and round, placed end to end'. Before that, it was often defined as the width of a thumb — hence the word in many languages (French: 'pouce', Dutch: 'duim'). The inch was standardised at exactly 25.4 mm in 1959 and remains dominant in the US and universally used for screen sizes globally.
Common use: Millimeter to Inch conversion is needed when working with international standards, scientific publications, or reference materials that use different unit systems for Length measurement.