Convert Kilometres per Hour to Millimetres per Second
Convert Kilometres per Hour (km/h) to Millimetres per Second (mm/s) instantly and accurately.
Conversion Formula
mm/s = km/h × 277.7777778
About Kilometres per Hour
A kilometre per hour (km/h) = 1/3.6 m/s - the universal road speed unit across most of the world. Walking pace ~5-6 km/h; jogging 9-12 km/h; elite marathon runners average 20-21 km/h. High-speed rail (TGV, Shinkansen, ICE) 250-350 km/h; TGV record 574.8 km/h. Category 5 hurricane ≥252 km/h; Thrust SSC land speed record 1,228 km/h (Mach 1.02). 1 km/h = 0.2778 m/s = 0.6214 mph = 0.5400 kn.
About Millimetres per Second
A millimetre per second (mm/s) is 10⁻³ m/s - the speed of slow industrial mechanisms and recognisable biological motion. FDM 3D printers move at 40-120 mm/s for perimeters and 150-300 mm/s for infill. Garden snails travel 0.5-1.5 mm/s; earthworms 3-5 mm/s. CNC finishing operations run 1-several hundred mm/s. Hydraulic precision slides work at mm/s for surface preparation. Ultrasound particle velocities in soft tissue are also in this range. 1 mm/s = 10⁻³ m/s.
Quick Reference Table
| Kilometres per Hour (km/h) | Millimetres per Second (mm/s) |
|---|---|
| 1 km/h | 277.778 mm/s |
| 2 km/h | 555.556 mm/s |
| 5 km/h | 1388.89 mm/s |
| 10 km/h | 2777.78 mm/s |
| 25 km/h | 6944.44 mm/s |
| 50 km/h | 13888.9 mm/s |
| 100 km/h | 27777.8 mm/s |