Convert Kilometres per hour per second to Millimetres per second squared
Convert Kilometres per hour per second (km/h/s) to Millimetres per second squared (mm/s²) instantly and accurately.
Conversion Formula
mm/s² = km/h/s × 277.7777778
About Kilometres per hour per second
The kilometre per hour per second (km/h/s) equals 1/3.6 m/s² ≈ 0.2778 m/s², the most intuitive acceleration unit for vehicle performance in countries using km/h. A 0-100 km/h time of 6.3 s (VW Golf GTI) gives a mean acceleration of 15.9 km/h/s ≈ 4.4 m/s²; a 2.6 s EV sprint corresponds to 38.5 km/h/s ≈ 10.7 m/s². Railway standards (EU TSI, JIS) use km/h/s: high-speed trains launch at 2.5-4 km/h/s; emergency braking must reach at least 9.0 km/h/s. 1 km/h/s = 1/3.6 m/s² ≈ 2.83 × 10⁻² g₀.
About Millimetres per second squared
The millimetre per second squared (mm/s²) equals 10⁻³ m/s², the standard unit for vibration acceleration in machine condition monitoring. ISO 10816 and ISO 20816 define machinery vibration limits in mm/s and mm/s²; ISO 10816-3 Zone A boundary for industrial machinery is ≈32 mm/s² at 2.2 Hz. Seismically, MMI VI ground shaking (masonry damage threshold) corresponds to 620-1250 mm/s² peak ground acceleration. 1 mm/s² = 10⁻³ m/s² ≈ 1.02 × 10⁻⁴ g₀.
Quick Reference Table
| Kilometres per hour per second (km/h/s) | Millimetres per second squared (mm/s²) |
|---|---|
| 1 km/h/s | 277.778 mm/s² |
| 2 km/h/s | 555.556 mm/s² |
| 5 km/h/s | 1388.89 mm/s² |
| 10 km/h/s | 2777.78 mm/s² |
| 25 km/h/s | 6944.44 mm/s² |
| 50 km/h/s | 13888.9 mm/s² |
| 100 km/h/s | 27777.8 mm/s² |