Wind Speed Converter
Convert wind speed between Beaufort scale, mph, km/h, knots, and m/s.
Includes Beaufort reference from calm to hurricane force with land and sea descriptions.
Wind Speed Conversion
Wind speed is measured in multiple units worldwide — knots (nautical miles per hour) in aviation and maritime, km/h in most weather forecasts, mph in the United States, and m/s in scientific contexts. The Beaufort scale translates speed into observable descriptions of wind effects, which is useful when you don’t have instruments.
Conversion formulas: knots × 1.852 = km/h km/h × 0.621 = mph m/s × 3.6 = km/h mph × 0.447 = m/s
Beaufort Scale reference:
| Beaufort | mph | km/h | Description |
|---|---|---|---|
| 0 | 0 | 0 | Calm — smoke rises vertically |
| 1 | 1–3 | 1–5 | Light air — smoke drifts |
| 2 | 4–7 | 6–11 | Light breeze — leaves rustle |
| 3 | 8–12 | 12–19 | Gentle breeze — twigs move |
| 4 | 13–18 | 20–28 | Moderate breeze — branches sway |
| 5 | 19–24 | 29–38 | Fresh breeze — small trees sway |
| 6 | 25–31 | 39–49 | Strong breeze — large branches sway |
| 7 | 32–38 | 50–61 | Near gale — whole trees sway |
| 8 | 39–46 | 62–74 | Gale — difficult to walk |
| 9 | 47–54 | 75–88 | Strong gale — roof damage |
| 10 | 55–63 | 89–102 | Storm — trees uprooted |
| 11 | 64–72 | 103–117 | Violent storm — widespread damage |
| 12 | 73+ | 118+ | Hurricane force |
Worked example: A forecast shows 45 knots. 45 × 1.852 = 83.3 km/h = 51.7 mph → Beaufort 9 (Strong Gale)