What Is the Base Unit of Measure for Length in the Metric System?

The meter is the metric system's base unit of length. Since 1983, the meter has been defined as the distance light travels in 1/299,792,458 of a second. The earliest definition of a meter had it as the one ten-millionth of the distance from the equator to the North Pole.

The meter is about 3 feet and 3 inches long. The unit was created out of a need presented by the scientific revolution going on in Western Europe in the 17th and 18th centuries: how to accurately measure quantities in a way that would be understood across international borders. At the time, systems of measurement differed from place to place.

The meter was first established in 1795 in revolutionary France. When smaller or larger units for length are needed, units that are powers of 10 greater or less than the meter are used. For example, the centimeter is 1/100 of a meter, while a kilometer is equal to 1,000 meters.