Speed Converter
Converts speed between road, marine, aviation and scientific units. A knot is one nautical mile per hour, which is why it is used at sea and in the air but never on the road.
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The formula
result = value × (from factor ÷ to factor)
Each speed unit is defined by its size relative to the metre per second, so converting between any two is a single multiplication.
Every speed unit
| Unit | Symbol | In one metre per second |
|---|---|---|
| metre per second | m/s | 1 |
| kilometre per hour | km/h | 3.6 |
| mile per hour | mph | 2.2369363 |
| foot per second | ft/s | 3.2808399 |
| knot | kn | 1.9438445 |
| Mach | Ma | 0.00293867 |
Frequently Asked Questions
How fast is 100 km/h in mph?
62.14 mph. A quick mental estimate: multiply km/h by 0.6 and add a little.
What is a knot?
One nautical mile per hour — 1.852 km/h or 1.15078 mph. It ties directly to latitude, since a nautical mile is one minute of arc.
How fast is Mach 1?
About 1,225 km/h (761 mph) at sea level in standard conditions. It is not a fixed speed — the speed of sound falls with temperature, so Mach 1 is slower at altitude. This converter uses the sea-level value of 340.29 m/s.