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Convert between kilometers per hour, miles per hour, meters per second, feet per second, and knots. Instant, accurate speed unit conversions with real-world context examples.
Similar to highway driving speed (90-130 km/h)
This converter provides accurate mathematical conversions between standard speed units. Results are rounded for display purposes.
Speed conversions are based on internationally standardized unit definitions. For scientific or engineering applications requiring extreme precision, consult official metrology resources.
A speed converter is a tool that transforms speed measurements from one unit to another. Whether you need to convert kilometers per hour to miles per hour for a road trip abroad, understand wind speeds in knots for sailing, or convert meters per second for scientific calculations, this converter handles all common speed units instantly. Speed (or velocity) measures how fast an object moves relative to a reference point, expressed as distance traveled per unit of time.
Kilometers per hour (km/h) - The standard speed unit in most countries, used for road traffic, weather reports, and general purposes in metric system countries.
Miles per hour (mph) - The primary speed unit in the United States, United Kingdom, and a few other countries, commonly used for vehicle speedometers and speed limits.
Meters per second (m/s) - The SI base unit for speed, used in scientific contexts, physics calculations, and international standards.
Feet per second (ft/s) - Used primarily in American engineering, ballistics, and some specialized applications.
Knots (kn) - A nautical unit equal to one nautical mile per hour, used universally in aviation and maritime navigation.
| Speed | km/h | mph | m/s | ft/s | knots |
|---|---|---|---|---|---|
| Walking | 5 | 3.1 | 1.4 | 4.6 | 2.7 |
| City driving | 50 | 31.1 | 13.9 | 45.6 | 27.0 |
| Highway | 120 | 74.6 | 33.3 | 109.4 | 64.8 |
| High-speed train | 300 | 186.4 | 83.3 | 273.4 | 162.0 |
| Commercial aircraft | 900 | 559.2 | 250.0 | 820.2 | 485.9 |
To convert kilometers per hour to miles per hour, divide the km/h value by 1.60934. For example, 100 km/h equals approximately 62.14 mph. Our converter does this calculation automatically and shows the precise result.
In everyday use, speed and velocity are often used interchangeably. Technically, speed is a scalar quantity (just magnitude), while velocity is a vector (magnitude plus direction). For unit conversions, they're treated the same way since we're only dealing with the magnitude.
Knots are based on nautical miles, which are directly related to the Earth's geometry (one nautical mile equals one minute of latitude). This makes navigation calculations simpler, as distances on nautical charts correspond directly to latitude readings. One knot equals one nautical mile per hour.
Meters per second (m/s) is the SI base unit for speed and is used in scientific contexts for its precision and universality. However, 'accuracy' depends on context - all units can express speed with equal precision; they're just different scales for measuring the same phenomenon.
Mach 1 is the speed of sound, which varies with temperature and altitude. At sea level and 20 degrees Celsius, Mach 1 is approximately 343 m/s, 1,234 km/h, or 767 mph. The Mach number is not a fixed speed unit but a ratio of speed to the local speed of sound.
Most European countries use kilometers per hour (km/h) for road speeds and daily use. The UK is an exception, using miles per hour (mph) for road traffic. For scientific work, meters per second (m/s) is the international standard.
To convert knots to km/h, multiply by 1.852. For example, 20 knots equals 37.04 km/h. This is useful when interpreting marine weather forecasts or aviation weather reports, which typically use knots.
Most conversion factors used here are exact or defined values. For example, 1 mile is exactly 1.609344 kilometers, and 1 nautical mile is exactly 1.852 kilometers. The m/s is the SI base unit, so other conversions are derived from these defined relationships.