The millimeter is an international unit for measuring very small lengths. It equals 0.001 meters and 0.1 centimeters.
Like the other metric units in the International System of Units (SI), the millimeter is defined in relation to the base unit meter, namely as one thousandth (“milli”) of a meter. On a standard metric ruler the millimeter is the smallest unit of measurement. A fine human hair is about 0.04mm thick. The focal length of photo lenses is typically specified in millimeters.
| Millimeters | |
|---|---|
| Marathon | 42,195,000.0 |
| Race track "Mille Miglia" | 1,609,300,000.0 |
| Earth radius | 6,378,165,000.0 |
| Earth circumference | 40,075,192,000.0 |
| Distance earth ↔ moon | 384,400,000,000.0 |
| Distance earth ↔ sun | 149,593,780,000,000.0 |