Miles per hour
mph
Kilometers per hour
km/h
Meters per second
m/s
Knot
kn
Feet per second
ft/s
Mach (at sea level)
Mach
Click any field to use it as your input — all other units update instantly.
Speed Converter
Convert between mph, km/h, m/s, knots and more. Instant speed and velocity conversion.
How to convert speed units online for free
- Type any speed value into one of the fields above (no signup needed)
- All units update instantly — km/h, mph, m/s, knots, and Mach
- Click any result field to copy the value for use in navigation, engineering, or physics problems
Why use our Speed Converter?
Speed conversions matter for driving (speed limits when renting a car abroad), aviation (knots vs km/h), and science (m/s vs km/h). The differences are non-trivial: 100 km/h is 62.1 mph, which matters if you are not used to the local speed limit signs.
Our converter includes Mach for engineers and aviation enthusiasts, plus knots for maritime and flight navigation. All units update simultaneously — just type once and read the result in whichever format you need.
Everything runs in your browser. No account, completely free.
Frequently asked questions
- How do I convert mph to km/h?
- Multiply the mph value by 1.60934. For example, 60 mph × 1.60934 = 96.56 km/h. Type in the mph field above and the km/h result appears instantly.
- What is a knot in km/h?
- One knot equals exactly 1.852 km/h, or 1.15078 mph. Knots are the standard unit for speed in aviation and maritime navigation.
- How do I convert m/s to km/h?
- Multiply by 3.6. For example, 10 m/s × 3.6 = 36 km/h. Conversely, divide km/h by 3.6 to get m/s.
- How fast is Mach 1 in km/h?
- Mach 1 (the speed of sound at sea level) is approximately 1,235 km/h (767 mph or 343 m/s) in dry air at 20°C. It varies with temperature and altitude.
- What is the speed of light in km/h?
- The speed of light is approximately 1,079,252,848 km/h (about 299,792 km/s or 186,282 miles per second). It is a fundamental physical constant.