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| Unit | Symbol | Used In | 1 Unit = (in m/s) |
|---|---|---|---|
| Meters per second | m/s | Physics, engineering, athletics | 1 |
| Kilometers per hour | km/h | Road speed (Europe, Asia, Australia, Canada) | 0.277778 |
| Miles per hour | mph / mi/h | Road speed (US, UK, Liberia, Myanmar) | 0.44704 |
| Knot | kn / kt | Maritime navigation, aviation | 0.514444 |
| Mach | M / Ma | Aerospace, supersonic flight | 343 (sea level, 20°C) |
| Speed of light | c | Theoretical physics, astronomy | 299,792,458 (exact) |
| Feet per second | ft/s | Ballistics, sports (baseball, tennis serve) | 0.3048 |
| Inches per second | in/s | Manufacturing, industrial automation | 0.0254 |
| Feet per minute | ft/min | HVAC, ventilation, elevators | 0.00508 |
| Feet per hour | ft/h | Geology, groundwater flow | 0.0000847 |
| Kilometers per second | km/s | Astronomy, spaceflight, orbital mechanics | 1000 |
| Meters per hour | m/h | Industrial processes, slow flow rates | 0.0002778 |
| Kine | — | Centimeters per second (CGS unit, historical) | 0.01 |
Maritime and aviation use knots because one knot equals one nautical mile per hour, and one nautical mile equals one minute of latitude — which makes navigation math on a spherical Earth dramatically simpler. Pilots and ship captains don't care about kilometers or statute miles; they care about angular distance on the globe. Physics and engineering use m/s because the meter and the second are SI base units — every derived formula (force, energy, power) expects m/s as input without conversion factors.
Automotive uses km/h or mph because road distances are in kilometers or miles, and 100 km/h maps intuitively to "I'll cover 100 km in an hour." Aerospace uses Mach number because the behavior of air around an aircraft changes fundamentally at the speed of sound — shock waves, drag coefficients, engine intake design all depend on Mach number, not absolute speed. Sports uses ft/s (US) or m/s (elsewhere) because a baseball pitcher's throw or a tennis serve covers 60 feet or 18 meters in under a second — the unit matches the scale of the action.
All conversions use meters per second (m/s) as the base unit. Input value → convert to m/s using the unit's factor → convert to all other units. This ensures every conversion is a single multiplication or division, avoiding accumulated rounding errors:
mph → m/s: mph × 0.44704 · km/h → m/s: km/h ÷ 3.6 · knots → m/s: knots × 0.514444 · mach → m/s: mach × 343 · c → m/s: c × 299,792,458
Enter your mph value in the "Miles per hour (mi/h)" field. The km/h field updates instantly. Formula: mph × 1.60934 = km/h. 60 mph = 96.56 km/h.
Mach 1 equals the speed of sound: 343 m/s, 1,234.8 km/h, or 767.27 mph at sea level (20°C / 68°F). The actual speed of sound varies with altitude, temperature, and humidity — this converter uses the standard sea-level value.
One knot = one nautical mile per hour. A nautical mile equals exactly one minute of latitude (1/60th of a degree). This makes navigation calculations on charts and globes far simpler — speed directly relates to angular distance, which is what navigators actually measure.
Light travels at 299,792,458 m/s — approximately 1,079 million km/h or 670 million mph. In more relatable terms: light circles the Earth's equator 7.5 times in one second, and sunlight takes about 8 minutes 20 seconds to reach Earth from the Sun.
A kine is the CGS (centimeter-gram-second) unit of speed: centimeters per second (cm/s). 1 kine = 0.01 m/s. It's largely obsolete but still appears in some engineering and scientific literature, particularly from the pre-SI era.