# Kilometers Per Second to Mach Number Conversion

Enter the speed in kilometers per second below to get the value converted to Mach number.

**Results in Mach Number:**

## How to Convert Kilometers Per Second to Mach Number

To convert a kilometer per second measurement to a Mach measurement, multiply the speed by the conversion ratio. One kilometer per second is equal to Mach 2.915452, so use this simple formula to convert:

The Mach number is equal to the speed in kilometers per second multiplied by 2.915452.

**For example,**here's how to convert 5 kilometers per second to Mach number using the formula above.

Kilometers per second and Mach number are both units used to measure speed. Keep reading to learn more about each unit of measure.

## Kilometers Per Second

Kilometers per second are a measurement of speed expressing the distance traveled in kilometers in one second.

The kilometer per second, or kilometre per second, is an SI unit of speed in the metric system. Kilometers per second can be abbreviated as *km/s*, and are also sometimes abbreviated as *km/sec*. For example, 1 kilometer per second can be written as 1 km/s or 1 km/sec.

In formal expressions, the slash, or solidus (/), is used to separate units used to indicate division in an expression.^{[1]}

Kilometers per second can be expressed using the formula:

v_{km/s} = d_{km}t_{sec}

The velocity in kilometers per second is equal to the distance in kilometers divided by time in seconds.

## Mach Number

Mach, sometimes also referred to as a Mach number, is the ratio of the speed of an object to the speed of sound.^{[2]}

Mach can be abbreviated as M, and is also sometimes abbreviated as Ma. For example, Mach 1 can be written as 1 M or 1 Ma.

Although Mach can be abbreviated *M* or *Ma*, the Mach number is typically expressed with the number after the unit name.
For example, the expression *Mach 3* is preferred rather than *3 Machs* or *3 M*.

The speed is classified as either subsonic, transonic, supersonic, or hypersonic depending on the Mach number.

Speed Classification | Mach Number |
---|---|

Subsonic | Mach < 1.0 |

Transonic | Mach = 1.0 |

Supersonic | Mach > 1.0 |

Hypersonic | Mach > 5.0 |

## Kilometer Per Second to Mach Conversion Table

Kilometers Per Second | Mach Number |
---|---|

0.08575 km/s | Mach 0.25 |

0.1715 km/s | Mach 0.5 |

0.25725 km/s | Mach 0.75 |

0.343 km/s | Mach 1 |

0.5145 km/s | Mach 1.5 |

0.686 km/s | Mach 2 |

0.8575 km/s | Mach 2.5 |

1.029 km/s | Mach 3 |

1.2005 km/s | Mach 3.5 |

1.372 km/s | Mach 4 |

1.5435 km/s | Mach 4.5 |

1.715 km/s | Mach 5 |

1.8865 km/s | Mach 5.5 |

2.058 km/s | Mach 6 |

2.2295 km/s | Mach 6.5 |

2.401 km/s | Mach 7 |

2.5725 km/s | Mach 7.5 |

2.744 km/s | Mach 8 |

2.9155 km/s | Mach 8.5 |

3.087 km/s | Mach 9 |

3.2585 km/s | Mach 9.5 |

3.43 km/s | Mach 10 |

## References

- National Institute of Standards and Technology, NIST Guide to the SI, Chapter 6: Rules and Style Conventions for Printing and Using Units, https://www.nist.gov/pml/special-publication-811/nist-guide-si-chapter-6-rules-and-style-conventions-printing-and-using
- NASA, Mach Number, https://www.grc.nasa.gov/WWW/BGH/mach.html