Speed Units Around the World: MPH, KPH, Knots, and More
Learn how different speed units are used worldwide and how to convert between them.
Speed measurement varies significantly around the world. Understanding different speed units is important for travel, sports, weather reports, and scientific work.
Common Speed Units
Kilometers per Hour (km/h)
Used by most countries worldwide for road speeds. Speed limits in Europe, Asia, South America, and most of Africa are posted in km/h.
Miles per Hour (mph)
Used primarily in the United States, United Kingdom, and a few other countries. If you are driving in the US or UK, you will see speed limits in mph.
Meters per Second (m/s)
The SI unit of speed, used in scientific contexts. Wind speed in weather reports is often given in m/s in many countries.
Knots (kn)
Used in maritime and aviation worldwide. One knot equals one nautical mile per hour (1.852 km/h). Even countries that use km/h for road speed use knots for sea and air navigation.
Mach Number
Used in aerospace to express speed relative to the speed of sound. Mach 1 is approximately 343 m/s (1,235 km/h) at sea level. Fighter jets can exceed Mach 2.
Key Conversions
- 1 mph = 1.609 km/h
- 1 km/h = 0.621 mph
- 1 knot = 1.852 km/h = 1.151 mph
- 1 m/s = 3.6 km/h = 2.237 mph
- Mach 1 ≈ 343 m/s ≈ 1,235 km/h ≈ 767 mph
Speed Limits Comparison
Highway speed limits vary dramatically by country:
- Germany (Autobahn): No limit on some sections
- USA: 65-75 mph (105-120 km/h)
- UK: 70 mph (112 km/h)
- France: 130 km/h (81 mph)
- Japan: 100-120 km/h (62-75 mph)
- Australia: 110-130 km/h (68-81 mph)
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