Mach 1 is the speed of sound, approximately 343 m/s or 1,235 km/h or 767 mph at sea level and 20°C.

A knot is one nautical mile per hour, equal to 1.852 km/h. It is used in aviation and maritime navigation.

Speed Converter

Convert between km/h, mph, m/s, ft/s, knots and Mach

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Key Formulas

1 km/h = 0.621371 mph

1 m/s = 3.6 km/h

1 knot = 1.852 km/h

Mach 1 = 343 m/s (at sea level, 20°C)

How Speed Conversion Works

Speed measures distance traveled per unit of time. Different fields use different units: road traffic (km/h, mph), science (m/s), aviation and marine (knots), and aerospace (Mach).

Common Speed Units

km/h: Kilometers per hour, used in most countries for road speed.
mph: Miles per hour, used in the US and UK for road speed.
m/s: Meters per second, the SI unit of speed.
Knots: Nautical miles per hour, used in aviation and maritime.
Mach: Ratio of speed to the speed of sound (~343 m/s at sea level).

Frequently Asked Questions

How do you convert km/h to mph?

Divide km/h by 1.60934 to get mph. Example: 100 km/h = 62.14 mph.

What is Mach 1?

Mach 1 is the speed of sound, approximately 343 m/s or 1,235 km/h at sea level and 20°C.

What is a knot?

A knot equals one nautical mile per hour (1.852 km/h). Used in aviation and maritime navigation.

How fast is the speed of light?

About 299,792,458 m/s or roughly 1,079,252,849 km/h.

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