Speed Converter

Convert between km/h, mph, m/s, knots, and Mach.

...
1 Kilometers per Hour (km/h) =
0.621372 Miles per Hour (mph)
1 Kilometers per Hour (km/h) =
0.277778 Meters per Second (m/s)

What is a Speed Converter?

A Speed Converter calculates velocity across different measurement contexts. While a car speedometer reads km/h or mph, a pilot relies on Knots or Mach numbers, and a physicist works in meters per second (m/s). This tool bridges those worlds.

Speed isn't just distance over time; it's the language of movement in different industries. On land, the world is divided between Kilometers per Hour (global standard) and Miles per Hour (US/UK). At sea and in the air, 'Knots' (nautical miles per hour) is the universal standard because it correlates with the Earth's latitude.

For high-speed aviation and ballistics, we use 'Mach'—the speed of sound. Mach 1 (approx 1235 km/h at sea level) is the sound barrier. Commercial jets cruise around Mach 0.8, while fighter jets can exceed Mach 2. Our converter relies on the 'Standard Atmosphere' model (15°C at sea level) for Mach calculations.

1How to Use

  • Type the speed value (e.g., 65).
  • Select the 'From' unit (e.g., MPH for a car speed).
  • Select the 'To' unit (e.g., Meters per Second).
  • The exact conversion appears instantly.
  • Use the swap button to check the reverse (e.g., what is 100 m/s in MPH?).

Key Features

  • 5 Key Units: KM/H (Land), MPH (US/UK Roads), Knots (Sea/Air), M/S (Physics), and Mach (Supersonic).
  • Mach Accuracy: Uses the standard speed of sound (343 m/s) for Mach conversions.
  • Physics Ready: Meters per Second (m/s) is the SI unit for all scientific calculations.
  • Instant & Precise: No page reloads; 6-decimal precision for technical use.

Frequently Asked Questions