# Speed of sound conversions

The speed of sound conversion selector on this page selects the speed/velocity measurement unit to convert to starting from speed of sound. To make a conversion starting from a unit of speed other than speed of sound, simply click on the "Reset" button.

## About speed of sound

The **speed of sound** is the distance traveled by a sound wave through an elastic medium during a period of time. In dry air at 20 °C (68 °F), the speed of sound is equal to 343.2 meters per second (m/s), the derived unit of speed in the International System of Units (SI).

The speed of sound is also equal to approximately 1,236 kilometers per hour (km/h), or 1,126 feet per second (ft/s), or 768 miles per hour (mph), or approximately one mile in five seconds or about one kilometer in three seconds.

The speed of sound varies depending on the medium the sound wave travels. Specifically, the sound wave travels faster in liquids and non-porous solids than it does in air:

- The speed sound travels through water at 20 °C (68 °F) is about 1,484 m/s (i.e., nearly 4.3 times faster than in dry air at the same temperature)
- The speed sound travels through iron at 20 °C is about 5,120 m/s (i.e., about 15 times faster than in dry air at the same temperature)

Plural: speed of sound