Speed Converter

How to use the speed converter

1. Type the speed you want to convert.
2. Choose the unit you are converting from and the unit you want to convert to.
3. The answer appears as you type, along with the same speed in every other unit on the page. Use Swap units to reverse the conversion.

Units and values used

All conversions go through meters per second. Most factors follow exactly from the definitions of the meter, the foot, the mile and the nautical mile.

• 1 kilometer per hour = 1,000 ÷ 3,600 meters per second (about 0.27778)
• 1 mile per hour = 0.44704 meters per second (exactly)
• 1 knot = 1,852 meters per hour (one nautical mile per hour), about 0.51444 meters per second
• 1 foot per second = 0.3048 meters per second (exactly)
• 1 kilometer per second = 1,000 meters per second
• The speed of light in a vacuum (c) = 299,792,458 meters per second (exactly)
• 1 Mach = 340.29 meters per second, the speed of sound in air at sea level at 15 °C

Common conversions

• 100 km/h is about 62.14 mph.
• 60 mph is about 96.56 km/h.
• 1 m/s is exactly 3.6 km/h.
• 1 knot is about 1.852 km/h, or 1.1508 mph.
• 1 Mach is about 1,225 km/h, or 761 mph.

Good to know

• Mach is not a fixed speed. The speed of sound changes with temperature and altitude. This tool uses the standard sea-level value, so treat Mach results as approximate, especially for aircraft at high altitude.
• Knots are used in sailing and aviation. One knot is one nautical mile per hour.
• Rounding: results are shown to about 10 significant digits. Very large and very small results appear in scientific notation, such as 1.5e-9.
• Numbers: you can type commas, such as 1,250, and negative numbers are allowed.

Is it private?

Yes. Every conversion happens in your web browser. The numbers you enter are never uploaded or stored, and this tool needs no outside libraries.