Wind Speed Converter

The calculator uses a fixed priority order: km/h first, then m/s, then knots, and only falls back to the mph field once all three of the others read zero. So if you have a nonzero value in km/h and then also enter a value in knots, the km/h value still takes priority and the knots entry is ignored for that calculation -- clear the higher-priority field back to zero if you want a lower-priority one to take effect.

Yes -- these are standard, exactly-defined conversion factors (1 mph = 1.60934 km/h = 0.44704 m/s = 0.868976 knots), not approximations. Once you've entered a correct value in one field, the other three are mathematically derived from it with no rounding beyond normal display precision.

The Beaufort Scale groups continuous wind speed into 13 discrete numbered categories (0 through 12), each spanning an mph range -- Beaufort 4 ("Moderate Breeze"), for example, covers roughly 13 to 18 mph. Small speed changes that stay within the same category's range won't move the Beaufort number or its description, even though the precise mph, km/h, m/s, and knots values keep changing continuously underneath it.

It was originally developed in the early 1800s by Royal Navy officer Francis Beaufort as a way for sailors to estimate wind force from observed sea conditions without needing an instrument, later extended with land-based descriptions and standardized mph/km/h ranges. It remains a widely recognized way to communicate wind conditions in plain, descriptive terms rather than a raw speed number alone.

Clear the other three fields back to zero, then enter your value in the Wind Speed (knots) field -- since knots is checked after km/h and m/s but before falling back to mph, a nonzero knots value will be used as long as km/h and m/s are both zero. The mph, km/h, and m/s fields will then update to show the equivalent speeds.