Kilometers per Hour to Mach Number Converter

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


Result in Mach Number:

Loading content.
1 km/h = Mach 0.00081

Do you want to convert Mach number to kilometers per hour?

How to Convert Kilometers per Hour to Mach Number

To convert a kilometer per hour measurement to a Mach measurement, multiply the speed by the conversion ratio. One kilometer per hour is equal to Mach 0.00081, so use this simple formula to convert:

Mach number = kilometers per hour × 0.00081

The Mach number is equal to the speed in kilometers per hour multiplied by 0.00081.

For example, here's how to convert 5 kilometers per hour to Mach number using the formula above.
5 km/h = (5 × 0.00081) = Mach 0.004049
conversion scale showing kilometers per hour and equivalent Mach number speed values

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

What Are Kilometers per Hour?

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

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

In the expressions of units, the slash, or solidus (/), is used to express a change in one or more units relative to a change in one or more other units.[1] For example, km/h is expressing a change in length or distance relative to a change in time.

Kilometers per hour can be expressed using the formula:
vkm/h = dkm / thr

The velocity in kilometers per hour is equal to the distance in kilometers divided by time in hours.

Learn more about kilometers per hour.

What Is 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 classifications for various mach numbers.
Speed Classification Mach Number
Subsonic Mach < 1.0
Transonic Mach = 1.0
Supersonic Mach > 1.0
Hypersonic Mach > 5.0

Learn more about Mach number.

Kilometer per Hour to Mach Conversion Table

Mach numbers converted to Mach number
Kilometers Per Hour Mach Number
308.7 km/h Mach 0.25
617.4 km/h Mach 0.5
926.1 km/h Mach 0.75
1,235 km/h Mach 1
1,852 km/h Mach 1.5
2,470 km/h Mach 2
3,087 km/h Mach 2.5
3,704 km/h Mach 3
4,322 km/h Mach 3.5
4,939 km/h Mach 4
5,557 km/h Mach 4.5
6,174 km/h Mach 5
6,791 km/h Mach 5.5
7,409 km/h Mach 6
8,026 km/h Mach 6.5
8,644 km/h Mach 7
9,261 km/h Mach 7.5
9,878 km/h Mach 8
10,496 km/h Mach 8.5
11,113 km/h Mach 9
11,731 km/h Mach 9.5
12,348 km/h Mach 10


  1. National Institute of Standards and Technology, NIST Guide to the SI, Chapter 6: Rules and Style Conventions for Printing and Using Units,
  2. NASA, Mach Number,

More Kilometer per Hour & Mach Conversions