Speed Converter
Convert between speed units including km/h, mph, knots, m/s, and Mach.
km/h
All conversions from
Meter per Second
0.277777778 m/s
Kilometer per Second
0.0002777778 km/s
Mile per Hour
0.6213711927 mph
Mile per Second
0.0001726031 mi/s
Foot per Second
0.911344416 ft/s
Foot per Minute
54.6806649606 ft/min
Knot
0.5399568044 kn
Mach
0.0008162972 Ma
Speed of Light
9e-10 c
Centimeter per Second
27.7777778 cm/s
Inch per Second
10.9361329921 in/s
Frequently Asked Questions
To convert miles per hour (mph) to kilometers per hour (km/h), multiply by 1.60934. For example, 60 mph = 60 × 1.60934 = 96.56 km/h. To convert km/h to mph, divide by 1.60934 or multiply by 0.621371.
A knot equals one nautical mile per hour (1.852 km/h or 1.151 mph). The term dates from the 17th century when sailors measured speed using a rope with knots tied at regular intervals. Knots are used in navigation because one nautical mile equals one minute of latitude, making calculations easier.
The speed of light in a vacuum (c) is exactly 299,792,458 meters per second, or about 1.08 billion km/h (670.6 million mph). This is a fundamental constant of physics and represents the maximum speed at which information can travel.
To convert meters per second (m/s) to kilometers per hour (km/h), multiply by 3.6. For example, 10 m/s = 10 × 3.6 = 36 km/h. This is because there are 3,600 seconds in an hour and 1,000 meters in a kilometer (3600/1000 = 3.6).