Speed Converter
Convert between km/h, mph, m/s, knots, and ft/s instantly.
🏃 Supports m/s, km/h, mph, knots, and ft/s. Common use: converting speed limits between countries.
Common Speed Units
Speed is measured differently depending on context and country. km/h and mph dominate everyday driving, m/s is standard in physics and engineering, knots are used in aviation and maritime, and ft/s appears in some US engineering contexts.
Conversion Factors
- 1 km/h = 0.621371 mph = 0.277778 m/s
- 1 mph = 1.60934 km/h = 0.44704 m/s
- 1 m/s = 3.6 km/h = 2.23694 mph
- 1 knot = 1.15078 mph = 1.852 km/h
- 1 ft/s = 0.681818 mph = 0.3048 m/s
When You'll Need Speed Conversion
- Driving abroad: Speed limits in km/h (most countries) vs. mph (US, UK)
- Running & cycling: Pace often in min/km or min/mile
- Aviation: Airspeed measured in knots
- Weather: Wind speed in m/s, km/h, mph, or knots depending on country
- Physics problems: Almost always in m/s
Quick Mental Conversions
- km/h to mph: multiply by 0.6, or take 60% (100 km/h ≈ 62 mph)
- mph to km/h: multiply by 1.6 (60 mph ≈ 97 km/h)
- m/s to km/h: multiply by 3.6 (10 m/s = 36 km/h)
- knots to mph: add 15% (100 knots ≈ 115 mph)
Reference Speeds
- Walking: ~5 km/h (3 mph)
- Marathon runner (elite): ~20 km/h (12.4 mph)
- Highway speed limit: 100-130 km/h (60-80 mph)
- Commercial airliner (cruise): ~900 km/h (560 mph, ~486 knots)
- Speed of sound: ~1225 km/h (761 mph, Mach 1)
- Speed of light: ~1.08 billion km/h
What Is a Knot?
A knotis one nautical mile per hour, where a nautical mile is based on the Earth's circumference (one minute of latitude). Because nautical miles relate directly to navigation, knots remain the standard in aviation and maritime use worldwide, even in countries that use metric for everything else.
About the Speed Converter
The Speed Converter converts speed converterfrom one unit to another using the exact internationally defined conversion factors. Type a value, choose your source and target units, and the converted result is shown instantly — no waiting, no page reload.
Manual conversion is error-prone because it means memorizing ratios (how many feet in a meter, how many pints in a liter). This tool removes that friction: the conversion factor is built in, and the math is done to full precision with no rounding until the final displayed number.
How to Use This Tool
- Enter the value you want to convert in the input field.
- Select the unit you are converting from.
- Select the unit you want to convert to.
- The converted value appears instantly. Adjust either unit to compare across the board.
- Copy the result if you need it elsewhere. Your input is never sent anywhere.
Why Use an Online Converter?
Browser-based tools like this one have a few real advantages over installed software or manual methods:
- No installation. It opens instantly in any browser, on any operating system.
- Private by default. Everything runs locally, so your data stays on your device.
- Always up to date.There's nothing to update — you always get the latest version when you load the page.
- Free and unlimited. Use it as often as you like, with no account and no caps.
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