Speed describes distance traveled during a fixed time. Road signs, aviation reports, sports data, and engineering work often use different units. This converter compares them without manual factor lookup.
Convert kilometers per hour, miles per hour, meters per second, feet per second, knots, and Mach. Results update as you type and can be reversed with one swap. All calculations run locally in the browser.
Convert road, science, aviation, and marine speed units instantly as you type.
Select the starting speed unit, type a non-negative value, and choose the target unit. The result updates immediately and includes the active factor.
Use swap to reverse the pair without re-entering the value. Keep several decimal places for engineering work, then round according to the final use.
Kilometers per hour and miles per hour are common road units. Meters per second and feet per second are useful when distance and time need SI or engineering consistency.
A knot equals one nautical mile per hour. Mach is a ratio to the local speed of sound, so its physical value changes with atmospheric conditions.
Unit | Symbol | km/h |
|---|---|---|
| Kilometer per hour | km/h | 1 |
| Mile per hour | mph | 1.609344 |
| Meter per second | m/s | 3.6 |
| Foot per second | ft/s | 1.09728 |
| Knot | kn | 1.852 |
| Mach (reference) | Ma | 1,234.8 |
Convert the input to kilometers per hour, then divide by the target factor. This base-unit method covers every pair in the tool.
For example, 60 mph multiplied by 1.609344 equals 96.56064 km/h. The displayed result rounds only after the full calculation.
The examples cover road, running, marine, and technical speeds. Each uses the same factors shown in the reference table.
Check the scale as well as the digits. A mph-to-km/h result should be larger, while a km/h-to-mph result should be smaller.
Road limits commonly use km/h or mph, depending on the country. Convert before driving across a border rather than estimating from the dashboard scale.
Running platforms often report pace instead of speed. Pace is time per distance, so it requires an inverse calculation rather than a direct speed-unit factor.
Marine and aviation navigation use knots because nautical miles match Earth-based angular measurements. One knot equals exactly 1.852 km/h.
Mach 1 is not a fixed ground speed. This tool uses 1,234.8 km/h as a reference value near standard sea-level conditions, not a flight-planning correction.
Do not confuse speed with pace or distance. A speed value needs both a distance unit and a time unit, while distance alone cannot describe motion.
Mach values also need context because temperature affects sound speed. Use atmospheric flight data when safety or navigation depends on the result.
Mistake | Effect | Check |
|---|---|---|
| mph treated as km/h | About 61% scale error | Confirm the road unit |
| Speed confused with pace | Inverse result | Check distance per time versus time per distance |
| Mach treated as fixed | Atmospheric error | Use local temperature and altitude data |
Frequently Asked Questions