Millimeters Converter

The centimeter is exactly one hundredth of a meter, written 0.01 m, and it is the unit most metric rulers and tape measures are marked in, with ten millimeters to one centimeter.

It appears on clothing labels, school rulers, rainfall reports and body measurements, and in medicine for wound sizes. A person's height is commonly recorded in centimeters on metric forms.

The meter is the base unit of length in the International System, defined by the distance light travels in a vacuum in 1/299,792,458 of a second.

It measures room dimensions, fabric sold by the metre, athletic tracks, water depth and building heights. Scientific work uses meters and its decimal multiples, from nanometers to gigameters, almost everywhere outside everyday imperial trade.

The kilometer is exactly 1,000 meters, the unit of length in the International System used for distances between places rather than across a room. It is written km and is the basis of the metric road network.

Road signs, speed limits, odometers and race distances use kilometers in most of the world. Maps quote distances in kilometers, and athletic events such as the marathon are described in kilometers.

An inch is exactly 2.54 centimeters, or 25.4 millimeters. Twelve inches make one foot and thirty-six make a yard, so the inch sits inside two larger imperial units.

Screen and tyre sizes are given in inches, as are pipe and hose diameters, wrench openings and the diagonal of a television. Rainfall is still recorded in inches in some countries.

The foot is exactly 0.3048 meters, or twelve inches. United States survey work has used a separate survey foot, defined as 1200/3937 meters and equal to about 0.3048006 meters.

Aviation uses feet for altitude and flight levels worldwide, even in countries that measure road distance in kilometers. Building heights, room dimensions, timber and, in some places, body height are also quoted in feet.

The yard is exactly 0.9144 meters, three feet or thirty-six inches. It is a defined multiple of the meter, not an independent standard. Its value was fixed by the same international agreement that defined the foot and the inch.

Fabric, carpet and some flooring are still sold by the yard, and the chain and furlong used in land and horse racing are built from yards. American football is measured in yards.

The international mile is exactly 1,609.344 meters, or 1.609344 kilometers. It descends from the Roman mile of a thousand paces and remains the standard road distance in the United States and the United Kingdom.

Road signs and speed limits, distance markers on highways, running and cycling events and aviation track distances are quoted in miles in those countries. Nautical miles are separate and longer.