Wind Speed and Beaufort Converter
Convert wind speed between the Beaufort scale, km/h, mph, knots, and m/s.
Includes sea state and land effect descriptions for each Beaufort force level.
Type in any field — the others update instantly. Or select a Beaufort force.
The Beaufort scale classifies wind speed by observed conditions.
Speed conversions:
- 1 knot = 1.852 km/h = 1.15078 mph = 0.51444 m/s
- 1 m/s = 3.6 km/h = 2.23694 mph = 1.94384 knots
Beaufort scale reference:
| Force | Description | km/h | mph | knots | m/s |
|---|---|---|---|---|---|
| 0 | Calm | 0–1 | 0–1 | 0–1 | 0–0.2 |
| 1 | Light air | 1–5 | 1–3 | 1–3 | 0.3–1.5 |
| 2 | Light breeze | 6–11 | 4–7 | 4–6 | 1.6–3.3 |
| 3 | Gentle breeze | 12–19 | 8–12 | 7–10 | 3.4–5.4 |
| 4 | Moderate breeze | 20–28 | 13–18 | 11–16 | 5.5–7.9 |
| 5 | Fresh breeze | 29–38 | 19–24 | 17–21 | 8.0–10.7 |
| 6 | Strong breeze | 39–49 | 25–31 | 22–27 | 10.8–13.8 |
| 7 | Near gale | 50–61 | 32–38 | 28–33 | 13.9–17.1 |
| 8 | Gale | 62–74 | 39–46 | 34–40 | 17.2–20.7 |
| 9 | Strong gale | 75–88 | 47–54 | 41–47 | 20.8–24.4 |
| 10 | Storm | 89–102 | 55–63 | 48–55 | 24.5–28.4 |
| 11 | Violent storm | 103–117 | 64–72 | 56–63 | 28.5–32.6 |
| 12 | Hurricane | 118+ | 73+ | 64+ | 32.7+ |
Beaufort 6+ can make walking difficult. Beaufort 8+ can cause structural damage.
How we build and check this converter
This converter runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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