How to use the speed converter
This speed converter lets you switch between common speed units in one place. Choose the unit you are converting from and the unit you want to convert to, enter a non-negative value, and click "Convert" to see the result. A "Swap" button reverses the from and to units so you can check conversions in both directions without retyping. All conversions use meters per second as the base: every unit is defined relative to m/s, so the tool stays consistent and accurate.
Speed conversion is useful in many situations. When you travel or read about vehicles, you often see speeds in miles per hour (mph) in the US and UK, or in kilometers per hour (km/h) in most other countries. Aviation and maritime use knots (nautical miles per hour). Physics and engineering often use meters per second (m/s). High-speed aircraft speeds are sometimes given in Mach (multiples of the speed of sound). Whether you are comparing a car's top speed, checking a speed limit abroad, or working on a physics problem, having a single tool that handles m/s, km/h, mph, ft/s, knots, and Mach saves time and reduces errors.
The converter runs entirely in your browser. There is no sign-up, no download, and no delay. It is designed to be mobile-friendly: the two-column layout stacks on small screens, inputs have a comfortable touch size, and the result appears next to your input so you can compare at a glance. Results are shown with up to six decimal places when needed. Note that Mach uses a standard approximation for the speed of sound at sea level (about 343 m/s); actual speed of sound varies with altitude and temperature.
Bookmark this page for quick access whenever you need to convert speed between different units. Whether you are driving, flying, or calculating, this free speed converter provides fast, accurate, and easy-to-read results on any device.