Speed Converter
Type a number once — see it in every speed unit instantly.
Enter a number to see it in every speed unit.
All speed units at once
| Unit | Value |
|---|---|
| Meters per second (m/s) | — |
| Kilometers per hour (km/h) | — |
| Miles per hour (mph) | — |
| Feet per second (ft/s) | — |
| Knots (kn)1 nautical mile per hour = 1.852 km/h | — |
| Mach (sea level, 15°C)Reference: sea level, 15°C (≈340.29 m/s) | — |
자주 묻는 질문
How do I convert km/h to mph (and mph to km/h)?
To convert km/h to mph, multiply by 0.621371 — so 1 km/h = 0.6213711922 mph and 100 km/h ≈ 62.14 mph. Going the other way, multiply mph by 1.609344, so 1 mph = 1.609344 km/h and 60 mph ≈ 96.56 km/h. This converter does both directions at once: type a number, pick km/h → mph (or swap), and read every unit instantly.
What is a knot, and how does it relate to km/h and mph?
A knot is one nautical mile per hour, used in aviation and sailing. One knot equals exactly 1.852 km/h, which is about 1.15078 mph or 0.514444 m/s. So 10 knots ≈ 18.52 km/h ≈ 11.51 mph. Because a nautical mile is based on the Earth's circumference, knots are handy for navigation across latitude and longitude.
How do I convert m/s to km/h, and what is Mach?
To convert meters per second to km/h, multiply by 3.6 — so 1 m/s = 3.6 km/h and 10 m/s = 36 km/h. Feet per second (ft/s) uses a factor of 0.3048 m/s. Mach is the ratio to the speed of sound; this tool uses the standard sea-level value at 15°C, where Mach 1 ≈ 340.29 m/s ≈ 1225 km/h. The real speed of sound changes with altitude and temperature, so Mach here is a reference figure.
How precise are the results?
Every conversion keeps up to 10 significant figures, then trailing zeros are trimmed for readability. Very large or very small numbers (roughly 1e15 and above, or below 1e-9) switch to scientific notation, so nothing is silently rounded away to zero. The km/h, mph, ft/s and knot factors are exact by definition; only Mach depends on the chosen air condition.
Is my input sent to a server?
No. This speed converter runs entirely in your browser — the number you type is never uploaded anywhere. The only thing saved is your last chosen unit pair (for example km/h → mph), kept in your browser's local storage so it is ready next time. The value itself is not stored, and there are no accounts or trackers.