Weather reports quote wind in km/h, runners' watches often show pace in min/km, but physics hands you raw meters per second — and the only number you need to reconcile them is 3.6. That factor falls straight out of the clock: one meter per second sustained for an hour covers 3,600 meters, which is 3.6 kilometers. Type 10 into the m/s box and the km/h readout lands on exactly 36, while the mph box shows 22.3694 for the American audience. Push it to the extreme the schema invites — 299,792,458 m/s, the speed of light — and you get about 1.079 billion km/h, a playful reminder of how fast c really is. This conversion is daily bread for meteorologists turning model output into broadcast graphics, for cyclists comparing power-meter speeds, and for students checking whether their dynamics homework passes the smell test. The return trip is just division: km/h divided by 3.6 gives m/s, so a 90 km/h gust is exactly 25 m/s.

With the pre-filled defaults — m/s 10 — the m/s to km/h returns km/h 36.0000, mph 22.3694. Change any input and those results update instantly, so you can see exactly how each number you enter moves the answer.