An inch is the name of a unit of length in a number of different systems, including Imperial units, and United States customary units. There are 36 inches in a yard and 12 inches in a foot. The inch is usually the universal unit of measurement in the United States, and is widely used in the United Kingdom, and Canada, despite the introduction of metric to the latter two in the 1960s and 1970s, respectively. The inch is still commonly used informally, although somewhat less, in other Commonwealth nations such as Australia; an example being the long standing tradition of measuring the height of newborn children in inches rather than centimetres. The international inch is defined to be equal to 25.4 millimeters., More information from the unit converter How many inches in 1 mm? The answer is 0.039370078740157. We assume you are converting between inch and millimetre. You can view more details on each measurement unit: inches or mm The SI base unit for length is the metre. 1 metre is equal to 39.370078740157 inches, or 1000 mm. Note that rounding errors may occur, so always check the results. Use this , Conversion table inches to millimeterTo analyze data generated in the laboratory to determine its significance, you must first evaluate your data from a statistical perspective. The system of measurement, specifically the measurement of length, varies between the imperial and metric systems. An inch (symbol: in) is a unit of length in the common imperial (UK) and US systems of measurement. The .