Deterministic linear speed units. Mach is excluded as a fixed unit because the local speed of sound depends on medium and conditions.
All factors come from the central conversion registry.
| Unit | Symbol | System | Definition |
|---|---|---|---|
| Meters per Second | m/s | SI | 1 m/s = 1 m/s |
| Kilometers per Hour | km/h | Metric | 1 km/h = 0.277777… m/s |
| Miles per Hour | mph | US/UK | 1 mph = 0.44704 m/s |
| Feet per Second | ft/s | International | 1 ft/s = 0.3048 m/s |
| Centimeters per Second | cm/s | SI | 1 cm/s = 0.01 m/s |
| Knot | kn | Maritime/Aviation | 1 kn = 1852/3600 m/s |
| Speed of Light in Vacuum | c | SI defining constant | c = exactly 299,792,458 m/s |
Speed combines distance and time. Common road-speed units such as mph and km/h are linear, while a knot is one nautical mile per hour and therefore follows the exact nautical-mile definition.
The interactive calculator, reference table and indexed pair pages all read from the same conversion registry, so unit definitions and formulas stay synchronized.
Mach number is a ratio: object speed divided by the local speed of sound. The speed of sound changes with the medium and conditions such as temperature, so BQ Convert does not assign one universal Mach-to-mph or Mach-to-km/h multiplier.
Use this Speed converter for deterministic units such as m/s, km/h, mph, knots, cm/s and the defined speed of light in vacuum. For Mach calculations, first determine an appropriate local speed of sound for the conditions you are modeling.