Convert m/s, km/h, mph, knots, Mach, ft/s — road, sea, air and engineering.
Updated
| Unit | Value | Copy |
|---|---|---|
Millimetre per second mm/s | 16,666.66666667 | |
Centimetre per second cm/s | 1,666.66666667 | |
Metre per second m/s | 16.66666667 | |
Kilometre per hour km/h | 60 | |
Mile per hour mph | 37.28227153 | |
Knot (nautical mile / hour) kn | 32.39740821 | |
Foot per second ft/s | 54.68066492 | |
Mach (sea level, 15°C) Mach | 0.04897783 |
Quick start
Type a speed, pick the unit, read it in every other unit at once.
Enter the speed and pick its unit. Switching units converts the displayed value so the meaning is preserved.
Eight units — mm/s through Mach — update live. The source unit is highlighted.
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In-depth guide
Convert between eight speed units — including everyday km/h and mph, maritime knots, aviation Mach and engineering ft/s. Type a value, pick the source unit, every other unit updates live.
| Unit | Symbol | In m/s |
|---|---|---|
| Millimetre per second | mm/s | 0.001 |
| Centimetre per second | cm/s | 0.01 |
| Metre per second | m/s | 1 |
| Kilometre per hour | km/h | 0.277 8 |
| Mile per hour | mph | 0.447 04 |
| Knot (nm / h) | kn | 0.514 4 |
| Foot per second | ft/s | 0.304 8 |
| Mach (sea-level, 15 °C) | Mach | 340.29 |
Use this converter when you need a quick value across metric, imperial, data, time, or other unit systems. Use domain-specific engineering, lab, or compliance software when tolerances, significant figures, or standards must be formally controlled.
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1 knot = 1 nautical mile per hour = 1852 m / 3600 s ≈ 0.5144 m/s. The nautical mile (1852 m exactly since 1929) is one minute of latitude along any meridian, which is why knots are used in maritime and aviation navigation.
Mach 1 ≈ 340.29 m/s, the speed of sound in dry air at sea level and 15 °C (288.15 K). The actual local speed of sound depends on temperature: it's about 295 m/s at the cruise altitude of a commercial airliner (−50 °C). For precise aerodynamics, model the local atmosphere.
3600 seconds in an hour, 1000 metres in a kilometre. 3600 / 1000 = 3.6. So 10 m/s = 36 km/h, and a 100 km/h car is doing about 27.78 m/s.
1 km = 0.6214 mi exactly (1/1.609344). So 100 km/h ≈ 62.14 mph and 60 mph ≈ 96.56 km/h.
It's so much larger than every other unit (3×10⁸ m/s) that listing it forces the other rows into scientific notation for any reasonable input. If you need it, multiply m/s by 3.336 × 10⁻⁹.
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