Meters per second and kilometers per hour
The meter per second is the SI unit of speed: one meter traveled each second, which is exactly 3.6 km/h. Physics, engineering and wind speeds in scientific forecasts are given in meters per second.
A kilometer per hour is 1,000 meters per 3,600 seconds: exactly 1/3.6 m/s. Speed limits, car speedometers and weather reports use km/h in most countries.
Worked example
Convert 10 m/s: 10 × 3.6 = 36, so 10 meters per second is 36 kilometers per hour. Likewise 50 m/s = 180 km/h.
Estimating in your head
The factor is a short exact number, so mental math needs no rounding: multiply by 3.6.
Going the other way
To convert kilometers per hour to meters per second, divide by 3.6 (or multiply by 0.277777777778). The swap button between the boxes opens that page.
How this works
km/h = m/s × 3.6
1 m/s = 1 m/s and 1 km/h = ≈ 0.2777777778 m/s, both by definition, so the factor is their ratio: 3.6 exactly. Results drop binary floating-point noise beyond 15 significant digits and display at the precision you choose (6 significant figures by default). Copy result copies the full value.
Frequently asked
How many kilometers per hour are in a meter per second?
1 meter per second = 3.6 kilometers per hour, exactly. The value follows from the unit definitions, so it never changes.
How do I convert meters per second to kilometers per hour?
Multiply by 3.6. For example, 50 m/s × 3.6 = 180 km/h.
What is 100 m/s in kilometers per hour?
100 m/s = 360 km/h. The table next to the converter lists more common values.
Is the result rounded?
Only on screen. The page computes with the exact definitions and removes floating-point noise past 15 significant digits; pick 3 to 12 significant figures, or use Copy result for the full value.
Sources
- NIST SP 811 Appendix B.8 — Factors for units listed alphabetically
- Federal Register 59-5442 (1959) — Refinement of values for the yard and the pound
- Wikipedia — Knot (unit)
Reviewed Oct 17, 2026 · test vectors fixtures/units/speed/m-s-to-kmh/