Convert between mph, km/h, m/s, knots, and more with our free speed converter. Instantly see any speed in all major units at once — perfect for driving, running, aviation, sailing, and physics problems.
Speed Converter
Speed Unit Reference
Speed is the rate of change of position. The most common units are mph (used in the US and UK for road speed), km/h (used worldwide in most countries), m/s (the SI base unit for physics), knots (used in aviation and maritime), and Mach (speed relative to the speed of sound in air at ~343 m/s).
Common Speed Conversions
- 60 mph = 96.56 km/h = 26.82 m/s
- 100 km/h = 62.14 mph = 27.78 m/s
- Speed of sound (Mach 1) = 343 m/s = 767.3 mph = 1235 km/h
- 1 knot = 1.852 km/h = 1.151 mph
- Running pace of 6 min/mile ≈ 10 mph = 16.09 km/h = 4.47 m/s
Frequently Asked Questions
How do I convert mph to km/h?
Multiply mph by 1.60934 to get km/h. For example, 60 mph × 1.60934 = 96.56 km/h. As a quick estimate, multiply mph by 1.6. To go the other way, multiply km/h by 0.62137.
What is a knot in speed?
A knot is one nautical mile per hour. 1 knot = 1.852 km/h = 1.151 mph. Knots are used in maritime navigation and aviation because they align with nautical miles (based on Earth’s latitude degrees), making navigation calculations simpler.
What is Mach speed?
Mach 1 is the speed of sound in air at sea level (approximately 343 m/s or 767 mph at 20°C). Mach 2 is twice the speed of sound. Commercial airliners cruise at about Mach 0.85 (570 mph). The Concorde flew at Mach 2.04.
How fast is 100 km/h in mph?
100 km/h = 62.14 mph. This is also known as the “highway speed limit” in many European countries. A quick mental conversion: divide km/h by 1.6 to get approximate mph.
What is m/s and when is it used?
Meters per second (m/s) is the SI unit for speed and is used in scientific and engineering contexts. Wind speed in meteorology, particle speeds in physics, and athletic performance records are often expressed in m/s. 1 m/s = 3.6 km/h = 2.237 mph.