Convert kilometres per hour to metres per second

One kilometre per hour is 0.277777778 metres per second. To convert any amount, multiply by 0.277777778. Going the other way, one metre per second is 3.6 kilometres per hour.

Multiply the kilometre per hour figure by 0.277777778. So m/s = km/h × 0.277777778. For a quick mental estimate, dividing by about 3.6 gets you close enough for most everyday purposes.

One kilometre per hour is 100 km/h is a typical highway limit. Kilometres per hour is the speed-limit unit in every country except the US, the UK and a few small territories.

One metre per second is about walking pace is 1.4 m/s. Metres per second is the SI unit and the one physics uses, because it composes cleanly with the other base units. Wind speeds in meteorology are often reported this way.

Yes. Since the 1959 international yard and pound agreement, the imperial and metric systems are related by exact definitions rather than measurements — the inch is exactly 25.4 mm and the pound exactly 0.45359237 kg. Everything derived from those, including this conversion, is therefore exact. Round at the end rather than partway through, since rounding km/h before converting introduces an error the conversion then multiplies.