Speed Converter

Speed is the distance traveled per unit of time: speed = distance / time. Its SI unit is the meter per second (m/s). Road speeds are given in km/h or mph, ships and aircraft in knots, and fast aircraft as a Mach number, a multiple of the speed of sound.

Strictly, velocity is speed in a given direction, but for converting units the two are the same.

How to convert speed units

Type a value into any field, and every other unit is calculated at once. For example, a car at 100 km/h:

1. In m/s: divide by 3.6, since an hour has 3,600 seconds and a kilometer 1,000 meters.

   100 / 3.6 = 27.78 m/s

2. In mph: divide by 1.60934, the kilometers in a mile.

   100 / 1.60934 = 62.14 mph

Common conversions

The calculator's Mach number uses the speed of sound in air at sea level and 15 °C, 340.29 m/s. The speed of sound falls with temperature, so at cruising altitude Mach 1 is about 1,060 km/h.

Speed units

• Meter/second (m/s) - Meter/second is the SI unit for speed and represents the distance covered in meters per second.
  Conversion factors: 1 m/s = 3.6 km/h = 2.23694 mi/h = 3.28084 ft/s = 1.94384 knots = 1.9426 knots (UK) = 0.00293867 M = 0.06 km/min = 60 m/min

• Kilometer/hour (km/h) - Kilometer/hour measures the distance covered in kilometers per hour.
  Conversion factors: 1 km/h = 0.277778 m/s = 0.621371 mi/h = 0.911344 ft/s = 0.539957 knots = 0.539612 knots (UK) = 0.0008163 M = 0.016667 km/min = 16.6667 m/min

• Mile/hour (mi/h) - Mile/hour represents the distance covered in miles per hour.
  Conversion factors: 1 mi/h = 0.44704 m/s = 1.60934 km/h = 1.46667 ft/s = 0.868976 knots = 0.868421 knots (UK) = 0.0013137 M = 0.026822 km/min = 26.8224 m/min

• Foot/second (ft/s) - Foot/second denotes the distance covered in feet per second.
  Conversion factors: 1 ft/s = 0.3048 m/s = 1.09728 km/h = 0.681818 mi/h = 0.592484 knots = 0.592105 knots (UK) = 0.00089571 M = 0.018288 km/min = 18.288 m/min

• Knot (kt) - Knot is a unit of speed used in navigation and aviation, representing nautical miles per hour.
  Conversion factors: 1 knot = 0.514444 m/s = 1.852 km/h = 1.15078 mi/h = 1.68781 ft/s = 0.99936 knots (UK) = 0.00151178 M = 0.030867 km/min = 30.8666 m/min

• Knot (UK) (kt) - Knot (UK) is a unit of speed used in navigation and aviation in the United Kingdom, representing UK nautical miles per hour.
  Conversion factors: 1 knot (UK) = 0.514773 m/s = 1.853184 km/h = 1.151515 mi/h = 1.68889 ft/s = 1.00064 knots = 0.00151275 M = 0.030886 km/min = 30.8864 m/min

• Mach (M) - Mach (speed of sound) is a unit of speed that represents the ratio of an object's speed to the speed of sound in the surrounding medium.
  Conversion factors: 1 M = 340.29 m/s = 1,225.04 km/h = 761.21 mi/h = 1,116.44 ft/s = 661.47 knots = 661.05 knots (UK) = 20.42 km/min = 20,417.4 m/min

• Speed of Light - The speed of light is a universal constant denoting the speed at which light travels in a vacuum.
  Conversion factors: Speed of Light = 299,792,458 m/s = 1,079,252,848.8 km/h = 670,616,629.4 mi/h = 983,571,056.4 ft/s = 582,750,421.8 knots = 582,377,603 knots (UK) = 880,991.1 M = 17,987,547.5 km/min = 17,987,547,480 m/min

• Kilometer/minute (km/min) - Kilometer/minute measures the distance covered in kilometers per minute.
  Conversion factors: 1 km/min = 16.6667 m/s = 60 km/h = 37.2823 mi/h = 54.6807 ft/s = 32.3974 knots = 32.3767 knots (UK) = 0.0489778 M = 1,000 m/min

• Meter/minute (m/min) - Meter/minute denotes the distance covered in meters per minute.
  Conversion factors: 1 m/min = 0.0166667 m/s = 0.06 km/h = 0.0372823 mi/h = 0.0546807 ft/s = 0.0323974 knots = 0.0323767 knots (UK) = 0.000048978 M = 0.001 km/min

Frequently asked questions

How do I convert km/h to mph quickly?

Multiply by 0.6, or for more accuracy by 5/8: 80 km/h is about 50 mph. Going the other way, multiply mph by 1.6.

What is a knot?

One nautical mile per hour. A nautical mile is 1,852 m, one minute of latitude, which is why ships and aircraft use it: 1 knot is 1.852 km/h, or about 1.15 mph.