Convert Kilometres per Hour to Nautical Miles per Second

Convert Kilometres per Hour (km/h) to Nautical Miles per Second (nmi/s) instantly and accurately.

Conversion Formula

nmi/s = km/h × 0.000149988001

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 Nautical Miles per Second

A nautical mile per second (nmi/s) equals exactly 1,852 m/s - squarely in the hypersonic domain at approximately Mach 5.44 (ISA sea level). At this speed, kinetic energy per kilogram is ½ × 1852² ≈ 1.71 MJ/kg, comparable to a small shaped-charge detonation. Ballistic missile re-entry vehicles descend at roughly 3.8-7 nmi/s during the terminal phase; ICBM warheads at peak re-entry travel near 4-6 nmi/s. The US Navy's electromagnetic railgun programme aimed to accelerate 10 kg projectiles to approximately 1.7-2.5 nmi/s in test firings, giving them sufficient kinetic energy to destroy armoured targets without a warhead. Hypervelocity impact experiments at two-stage light-gas gun facilities reach similar speeds to simulate asteroid-impact cratering physics. The speed of sound in beryllium metal (the fastest known bulk acoustic medium) is approximately 12.9 nmi/s. 1 nmi/s = 1,852 m/s = 6,667.2 km/h = 3,600 kn ≈ Mach 5.44.

Quick Reference Table

→ Full Speed Converter