What is the SI unit of Length?

The metre (m) also called as meter (in the US) is the SI unit of length. It’s defined as the distance light travels in a vacuum in 1⁄299792458 seconds. The meter is based on the speed of light, which is about 300 million meters per second.

The meter is the base unit of length in the International System of Units (SI). Other units of length include:

Kilometers (km)

Millimeters (mm)

Centimeters (cm)

Decimeters

Thou (1⁄1000 of an inch)

Line (1⁄12 of an inch)

Inch (25.4 mm)

Foot (12 inches, 0.3048 m)

The meter is about 10% longer than a yard, and is equivalent to 39.37 inches, or 1.094 yards.