Kilometers per Hour to Meters per Second

Kilometers per hour and 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.

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.

Worked example

Convert 90 km/h: 90 × 0.2777777778 = 25, so 90 kilometers per hour is 25 meters per second. Likewise 20 km/h = 5.555555556 m/s.

Estimating in your head

Divide by 3.6 for a quick figure; it is off by about 0%. For 90 km/h that gives 25 m/s, against 25 exactly.

Going the other way

To convert meters per second to kilometers per hour, divide by 0.2777777778 (or multiply by 3.6). The swap button between the boxes opens that page.

m/s = km/h × 0.2777777778

1 km/h = ≈ 0.2777777778 m/s and 1 m/s = 1 m/s, both by definition, so the factor is their ratio: 0.2777777778 (rounded here; the page uses the full value). 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.