Speed converter — km/h, m/s, mph, knots, Mach

Divide the km/h value by 3.6. For example, 90 km/h ÷ 3.6 = 25 m/s. The formula is v [m/s] = v [km/h] / 3.6.

A knot is one nautical mile per hour (1 kn ≈ 1.852 km/h ≈ 0.5144 m/s). It is the standard speed unit in maritime and aviation navigation.

Mach number is the ratio of an object's speed to the speed of sound. At sea level, 20°C, Mach 1 = 343 m/s = 1234.8 km/h = 667 knots.

Multiply the mph value by 1.60934. For example, 60 mph × 1.60934 ≈ 96.56 km/h.

At sea level and 20°C, the speed of sound is about 343 m/s, which equals 1234.8 km/h or 667.1 knots.

Road speeds use km/h (Europe) or mph (USA, UK). Aviation and shipping use knots. Science uses m/s. Supersonic speeds are expressed in Mach.

Multiply the m/s value by 3.6. For example, 10 m/s × 3.6 = 36 km/h.

Instantaneous speed is speed at a given moment (e.g., a speedometer reading), while average speed is total distance divided by total time. This converter works with instantaneous speed values.

1 knot = 1 nautical mile/h = 1.852 km/h = 0.5144 m/s. A ship doing 20 knots travels at 37.04 km/h or 10.29 m/s.

A typical commercial jet (Boeing 737, Airbus A320) cruises at about 850–900 km/h, roughly Mach 0.78–0.82. The Concorde flew above Mach 2 (over 2400 km/h).