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Speed Converter calculator →
Speed Converter guide
The Speed Converter translates velocity measurements between meters per second, kilometers per hour, miles per hour, knots, and feet per second. It is useful for physics, driving, and aviation.
Worked examples
Convert km/h to mph
- Enter 100.
- Choose Kilometers/hour (km/h) as the From unit.
- Choose Miles/hour (mph) as the To unit.
Result: 100 km/h = 62.1371 mph
1 km/h is approximately 0.621371 mph. 100 × 0.621371 = 62.1371.
Convert knots to km/h
- Enter 10.
- Choose Knots (kn) as the From unit.
- Choose Kilometers/hour (km/h) as the To unit.
Result: 10 knots = 18.52 km/h
1 knot is exactly 1.852 km/h. 10 × 1.852 = 18.52.
Convert m/s to km/h
- Enter 10.
- Choose Meters/second (m/s) as the From unit.
- Choose Kilometers/hour (km/h) as the To unit.
Result: 10 m/s = 36 km/h
To convert m/s to km/h, multiply by 3.6 (since there are 60 seconds in a minute and 60 minutes in an hour). 10 × 3.6 = 36.
Tips
- •m/s is the standard SI unit for speed in physics.
- •knots are used globally in aviation and maritime navigation.
- •The speed of sound is approximately 343 m/s, or Mach 1.
Frequently asked questions
What is the difference between speed and velocity?
Speed is a scalar (how fast you are going). Velocity is a vector (how fast AND in what direction).
What is a knot?
A unit of speed equal to one nautical mile per hour. It is used in aviation and sailing.
Why are knots used instead of mph?
Because a nautical mile corresponds to one minute of latitude on Earth, making navigation and chart reading much easier.
What is the SI unit of speed?
Meters per second (m/s).
How do I convert m/s to km/h?
Multiply by 3.6. For example, 5 m/s = 18 km/h.
How do I convert km/h to m/s?
Divide by 3.6. For example, 72 km/h = 20 m/s.
What is the speed of light?
Approximately 299,792,458 m/s. This tool cannot currently convert speeds that large.
What is the speed of sound?
At sea level at 20°C, it is approximately 343 m/s (1,235 km/h, or 767 mph).
How many feet per second is 60 mph?
60 mph is exactly 88 feet per second.
What is Mach 1?
The speed of sound. Mach 2 is twice the speed of sound.
Can the speed be negative?
Speed itself cannot be negative. However, if using velocity, a negative sign indicates moving in the opposite direction.
What is terminal velocity?
The maximum speed an object reaches while falling through a fluid (like air), where the drag force equals gravity.
How fast is a fastball in km/h?
A 100 mph fastball is approximately 160.9 km/h.
Are the conversions exact?
Most are exact (like m/s to km/h). Some, like knots to mph, are rounded slightly by the calculator.
Can I convert acceleration?
No. This tool converts steady speed. Acceleration is a rate of change of speed (e.g., m/s²).
What is a nautical mile?
A unit of distance equal to 1,852 meters, used in maritime and aviation.
What is the typical highway speed in km/h?
Depending on the country, it ranges from 100 to 130 km/h.
Does the tool support Mach numbers?
No, it currently only supports m/s, km/h, mph, knots, and ft/s.