Speed Converter
Convert a speed between kilometers per hour, miles per hour, meters per second and knots. Enter a value and a starting unit, and see all four equivalents update live.
How to Use the Speed Converter
- Enter the speed value you want to convert.
- Select which unit that value is currently in.
- All four units — km/h, mph, m/s and knots — update instantly to show the equivalent speed.
Why Use This Tool?
What conversion factors are used?
All conversions route through meters per second as a common base: 1 km/h = 0.277778 m/s, 1 mph = 0.44704 m/s, and 1 knot = 0.514444 m/s. From there, the value is converted into every other unit, giving results accurate to 6 decimal places — precise enough for aviation, marine navigation, weather reports, and everyday vehicle speed comparisons.
What is a "knot" and who uses it?
A knot equals one nautical mile per hour (1.852 km/h) and is the standard speed unit in marine navigation, aviation and meteorology, including wind speed reports. This tool makes it easy to translate a knot-based reading into the more familiar km/h or mph.
Why do countries use different speed units?
Most of the world measures road speed in km/h under the metric system, while the United States, United Kingdom and a few other countries use mph. This tool is especially handy for travelers renting a car abroad, or anyone reading vehicle top-speed specs from an international source.
Does this run entirely in my browser?
Yes — every conversion is calculated instantly with JavaScript on your device. No data is uploaded or stored anywhere.