Speed Converter

Convert between meter/second, kilometer/hour, mile/hour, knot, foot/second, and many other speed and velocity units with scientific precision.

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Speed Units Explained

Meter/second (m/s)

The SI unit of speed and velocity. Represents distance of one meter covered in one second. 1 m/s = 3.6 km/h.

Common uses: Physics calculations, fluid dynamics, aerodynamics, scientific measurements.

Kilometer/hour (km/h)

Most common unit for everyday speed. 1 km/h = 0.2778 m/s. Universal standard for road speed limits.

Common uses: Speed limits, vehicle speedometers, weather wind speeds, cycling, running.

Mile/hour (mph or mi/h)

Imperial unit of speed. 1 mph = 1.60934 km/h = 0.44704 m/s. Standard in USA, UK, and some Commonwealth countries.

Common uses: US speed limits, vehicle speedometers, race speeds, aviation.

Knot (kt or kn)

Maritime and aviation speed unit. 1 knot = 1.852 km/h = 0.51444 m/s. One nautical mile per hour.

Common uses: Ship speeds, marine navigation, aviation speed, weather reports (wind speed).

Foot/second (ft/s)

Imperial unit of speed. 1 ft/s = 0.3048 m/s = 1.0973 km/h. Used in US engineering and physics.

Common uses: Fluid flow rates, wind speed, ballistics, HVAC systems.

Kilometer/second (km/s)

Large speed unit for high velocities. 1 km/s = 3600 km/h. Used for spacecraft and cosmic speeds.

Common uses: Spacecraft velocity, asteroid speeds, rocket propulsion, planetary motion.

Mach (20°C, 1 atm)

Speed relative to sound. 1 Mach ≈ 343 m/s (at sea level, 20°C). Mach 2 = twice sound speed.

Common uses: Aircraft speeds, supersonic flight, hypersonic vehicles, shock waves.

Velocity of Light in Vacuum (c)

Maximum possible speed in the universe. c = 299,792,458 m/s ≈ 1,079 million km/h. Fundamental physical constant.

Common uses: Physics, relativity, photonics, fundamental calculations.

Speed Conversions Quick Reference

  • 1 m/s: 3.6 km/h = 2.237 mph = 1.944 knots = 3.281 ft/s
  • 1 km/h: 0.2778 m/s = 0.6214 mph = 0.5399 knots
  • 1 mph: 1.609 km/h = 0.4470 m/s = 0.8690 knots
  • 1 knot: 1.852 km/h = 0.5144 m/s = 1.151 mph
  • 1 ft/s: 0.3048 m/s = 1.0973 km/h = 0.6818 mph
  • Speed of sound: ~343 m/s = ~1235 km/h = ~761 mph (at sea level)
  • Speed of light: ~300,000 km/s = ~186,000 mi/s

Real-World Speed Examples

  • Walking speed: ~1.4 m/s (5 km/h, 3.1 mph)
  • Jogging speed: ~2.5 m/s (9 km/h, 5.6 mph)
  • Running sprint: ~10 m/s (36 km/h, 22.4 mph)
  • Bicycle: ~6-8 m/s (22-29 km/h, 13-18 mph)
  • Car on highway: ~30 m/s (108 km/h, 67 mph)
  • Commercial airplane: ~250 m/s (900 km/h, 560 mph)
  • Supersonic aircraft (Mach 2): ~686 m/s (2470 km/h, 1535 mph)
  • Earth orbital velocity: ~7.8 km/s (28,000 km/h)
  • Wind (hurricane): ~50 m/s (180 km/h, 112 mph)

Important: Speed vs Velocity

  • Speed: How fast an object is moving (scalar - magnitude only)
  • Velocity: Speed with direction (vector - magnitude + direction)
  • Average speed: Total distance ÷ total time
  • Instantaneous speed: Speed at a specific moment
  • Relative speed: Speed of one object relative to another
  • Ground speed vs airspeed: Wind affects aircraft ground speed
  • Escape velocity: ~11.2 km/s from Earth surface

Maritime & Aviation Speed Standards

  • Ships measured in: Knots (nautical miles/hour)
  • Airplanes measured in: Knots or km/h (airspeed indicator)
  • Wind speed measured in: Knots or m/s (meteorology)
  • Speed of light constant: c = 299,792,458 m/s (exact definition)
  • Supersonic barrier: Mach 1 (~340 m/s at sea level, varies with temperature)
  • Hypersonic: Mach 5 or faster (~1700 m/s)