Speed Converter

Convert between mph, km/h, m/s, knots, mach, and more

Speed Units

Miles per Hour

mph

Kilometers per Hour

km/h

Meters per Second

m/s

Feet per Second

ft/s

Knots

kn (nautical mph)

Mach

Mach (at sea level)

Speed Comparisons

Distance/Time Calculator

Calculate speed, distance, or time using the formula: Speed = Distance / Time

Help

How to Use

Enter a value in any speed unit field, and all other units will automatically update with the converted values. Use the Distance/Time Calculator to solve for speed, distance, or time given the other two values.

Common Units
  • mph (miles per hour): Common in USA, 1 mile = 5,280 feet
  • km/h (kilometers per hour): Standard metric unit, used worldwide
  • m/s (meters per second): SI base unit, used in physics
  • ft/s (feet per second): Used in engineering and ballistics
Specialized Units
  • Knots: Nautical miles per hour, used in maritime and aviation. 1 knot = 1.852 km/h exactly
  • Mach: Speed relative to the speed of sound. Mach 1 ≈ 1,235 km/h (343 m/s) at sea level and 15°C. The actual speed of sound varies with temperature and altitude.
Quick Conversions
  • 1 mph = 1.60934 km/h
  • 1 km/h = 0.621371 mph
  • 1 m/s = 3.6 km/h (exact)
  • 1 m/s = 2.23694 mph
  • 1 knot = 1.852 km/h (exact)
  • Mach 1 ≈ 343 m/s (at sea level, 20°C)
Speed Comparisons
  • Walking: 3-5 km/h (2-3 mph)
  • Running: 10-20 km/h (6-12 mph)
  • Cycling: 15-30 km/h (9-19 mph)
  • City driving: 30-50 km/h (19-31 mph)
  • Highway: 100-130 km/h (60-80 mph)
  • Cheetah: 120 km/h (75 mph)
  • High-speed train: 300-350 km/h (186-217 mph)
  • Commercial jet: 900 km/h (560 mph, ~Mach 0.85)
  • Speed of sound: 1,235 km/h (767 mph, Mach 1)
Mental Math Tips
  • km/h to mph: Divide by 1.6 (or multiply by 0.6)
  • mph to km/h: Multiply by 1.6
  • m/s to km/h: Multiply by 3.6
  • km/h to m/s: Divide by 3.6