Beaufort Wind Scale

Convert wind speed to Beaufort number and back. Full reference table with descriptions, sea state, and land effects for all 13 Beaufort levels (0–12).

Wind Speed

Full Beaufort Scale Reference

Force	Speed Range (km/h)	Description	Sea State
0	0–1	Calm	Sea like a mirror
1	1–5	Light air	Ripples, no foam crests
2	6–11	Light breeze	Small wavelets
3	12–19	Gentle breeze	Large wavelets
4	20–28	Moderate breeze	Small waves, some whitecaps
5	29–38	Fresh breeze	Moderate waves, many whitecaps
6	39–49	Strong breeze	Large waves, foam crests, spray
7	50–61	Near gale	Sea heaps up, foam streaks
8	62–74	Gale	Moderately high waves, blown foam
9	75–88	Severe gale	High waves, dense foam, visibility affected
10	89–102	Storm	Very high waves, surface white with foam
11	103–117	Violent storm	Exceptionally high waves
12	≥118	Hurricane force	Air filled with foam, sea white

How to Use the Beaufort Wind Scale

Enter the known physical values in the corresponding fields.
Select the appropriate units if multiple options are available.
The unknown value is computed instantly from the formula.
Review the result and the formula explanation below.

Referência Rápida

De	Para
Speed of light	299,792,458 m/s
Gravity (g)	9.807 m/s²
Avogadro's number	6.022 × 10²³
Boltzmann const.	1.38 × 10⁻²³ J/K
Elementary charge	1.602 × 10⁻¹⁹ C
Planck's const.	6.626 × 10⁻³⁴ J·s

Casos de Uso

•Solving physics homework or exam problems with the correct formula.
•Verifying experimental measurements and calculations in the lab.
•Understanding physical relationships between quantities.
•Quick engineering calculations for design or estimation.

Perguntas Frequentes

What is the Beaufort scale?

The Beaufort scale is an empirical measure of wind speed based on observed sea and land conditions. It ranges from 0 (calm) to 12 (hurricane force).

Who invented the Beaufort scale?

The scale was devised in 1805 by Sir Francis Beaufort, a British Royal Navy officer. It was officially adopted by the British Navy in 1838.

What is Beaufort 12?

Beaufort 12 represents hurricane-force winds with sustained speeds of 64 knots (≥ 118 km/h). The sea is completely white with driving spray and visibility is severely affected.

What speed is a gale?

A gale corresponds to Beaufort 8 (34–40 knots / 62–74 km/h). A severe gale is Beaufort 9 (41–47 knots / 75–88 km/h).

How is wind speed measured?

Wind speed is typically measured by an anemometer. It can be expressed in knots, km/h, m/s, or mph. The Beaufort scale was originally designed for use without instruments.