Tool
Speed Converter
Convert between m/s, km/h, mph, knots, ft/s and Mach. Live reference table for all speed units.
Convert speeds in three steps
Works in any browser, on any device. No install required.
Enter a speed value
Type any number into the input field.
Select the unit
Choose the source unit — mph, km/h, knots, m/s, Mach, or ft/s.
Get all speed units at once
Every speed unit updates simultaneously as you type.
Speed units
All major units
MPH, km/h, m/s, knots, Mach, ft/s all in one place.
Live conversion
All units refresh instantly as you type. No submit button.
Aviation and marine
Knots and Mach for pilots, sailors, and engineers.
About the Speed Converter
Speed units vary by context: km/h and mph for road speeds, knots for maritime and aviation, m/s for physics and science, and Mach for supersonic flight. Road signs and speedometers in the US and UK use mph while most of the world uses km/h.
Common uses: understanding speed limits when travelling abroad, converting weather wind speeds, comparing vehicle performance specifications across regions, and aviation/sailing navigation.
Quick reference: 60 mph = 96.6 km/h, 100 km/h = 62.1 mph, 30 mph = 48.3 km/h. In aviation, speed is measured in knots — 1 knot = 1.852 km/h = 1.151 mph. In science and engineering, metres per second is the standard unit: 1 m/s = 3.6 km/h. Mach 1 at sea level is approximately 1,235 km/h (767 mph), though it varies with altitude and temperature.
Wind speeds in weather forecasts use km/h in most countries and mph in the US and UK. The Beaufort scale uses knots as its baseline. Car and motorcycle performance figures are usually given in both mph and km/h in manufacturer specifications. This converter handles all of those contexts in one place.
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Use itFrequently Asked Questions
How do I convert mph to km/h?
1 mph = 1.60934 km/h. Quick estimate: multiply by 1.6. 60 mph ≈ 96 km/h.
What is a knot in mph and km/h?
1 knot = 1 nautical mile per hour = 1.852 km/h = 1.151 mph. Standard in aviation and maritime navigation.
What is Mach 1?
Mach 1 is the speed of sound — approximately 343 m/s or 1,235 km/h (767 mph) at sea level at 20°C.
How fast is the speed of light in mph?
Approximately 670,616,629 mph. The cosmic speed limit — nothing with mass can reach it.