How to convert millimeters to inches
Divide by 25.4. An inch has been exactly 25.4 mm since 1959, so the answer is as precise as your measurement.
A 300 mm rule works out at 11.81 inches – a fraction short of the foot it's pretending to be.
For a rough figure in your head, divide by 25 instead. That makes 300 mm about 12 inches, which is under 2% out: fine for picking a shelf bracket, not for machining anything.
What are millimeters?
Millimeters are a small unit of length measurement in the metric system. One millimeter is equal to a thousandth of a meter. This means that millimeters are used when measuring small distances or dimensions such as the thickness of a sheet of paper or a small object.
Millimeters are widely used worldwide especially in engineering. They provide a convenient unit of measurement for fine details.
Millimeters are used in the fashion industry for jewelry and fabric widths. Millimeters are also used in meteorology to record rainfall or snowfall.
1000mm is equal to a meter which is the SI unit of length.
What are inches?
Inches are commonly used in the United States and the United Kingdom. An inch is defined as one twelth (1/12th) of a foot and used to measure small distances like the length of a pencil or the width of a book.
Inches are often used in construction, carpentry and engineering. They are also often found in the fashion industry for determining clothing sizes and are used to specify screen sizes for TVs and computer monitors.
To convert inches to other units you need to know the appropriate conversion factor. For example, to convert inches to centimeters you need to multiply the inch value by 2.54. To convert inches to millimeters the inch measurement is multiplied by 25.4.
Inches are used mainly in the United States but it is common to find people using inches in the United Kingdom especially for body measurements, trades and fashion. Inches are a standard worldwide in electronics and semiconductors.
Some common Millimeters to Inches conversions
1mm to inches = 0.03937in
Which countries use millimeters?
A majority of countries worldwide have adopted the metric system and as such use millimeters.
In these countries millimeters are the preferred unit for measuring dimensions of building materials, such as pipes, beams, and panels. Millimeters are found in manufacturing for precision measurements, machinery, and tools. Millimeters are also used in medicine and are used in the fashion and textile industry.
Which countries use inches?
The United States is the most notable country that uses inches but a large number of people still use them in the United Kingdom as well. In the US, inches are the standard in construction and engineering. Inches are also common in determining a person's height or the size of television screens.
Although the UK has officially adopted the metric system, inches are still found in certain area particularly in construction. This is due to the historical influence of the imperial system. In the UK inches are also used for body height and objects that were traditionally measured this way such as vinyl records.