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Conversions

Speed Converter

Convert between metres per second, km/h, mph, knots, feet per second, and Mach instantly.

What is Speed Converter?

A speed converter lets you switch between different units of velocity used in everyday life, transportation, aviation, and science. Common units include kilometres per hour (km/h) for road travel, miles per hour (mph) in the US and UK, knots (kn) in maritime and aviation, and metres per second (m/s) in physics. Mach number expresses speed relative to the speed of sound.

How to use

  1. 1 Enter the speed value in the Value field.
  2. 2 Select the unit you are converting from in the From dropdown.
  3. 3 Select the unit you want to convert to in the To dropdown.
  4. 4 The result and a full table of all equivalent speeds appear instantly.
  5. 5 Click the swap button to reverse the conversion.

Formula

converted = input_value * (factor_of_from_unit / factor_of_to_unit), where all factors are expressed relative to metres per second

Example calculation

To convert 100 km/h to mph: 100 km/h × (1/3.6) m/s per km/h = 27.78 m/s, then 27.78 m/s / 0.44704 m/s per mph = 62.14 mph.

Frequently asked questions

What is 1 knot in km/h?

One knot equals approximately 1.852 km/h. Knots are the standard speed unit used in maritime and aviation navigation, defined as one nautical mile per hour.

What is Mach 1 in km/h?

Mach 1 (the speed of sound at sea level, 15 degrees Celsius) is approximately 340.29 m/s, which equals about 1225 km/h or 761 mph. The exact value varies with air temperature and altitude.

How do I convert mph to km/h?

Multiply miles per hour by 1.60934 to get kilometres per hour. For example, 60 mph × 1.60934 = 96.56 km/h. To go the other way, multiply km/h by 0.62137.

Why do pilots use knots instead of km/h or mph?

Knots are tied directly to nautical miles, which correspond to degrees of latitude. This makes navigation and distance calculations more intuitive on charts and in flight computers.

What is the speed of light in km/h?

The speed of light in a vacuum is approximately 299,792,458 m/s, which equals about 1.079 billion km/h. It is the universal speed limit and used as a reference in physics and astronomy.