About

Accurate wind speed conversion is critical for maritime safety, aviation flight planning, and structural engineering. While basic converters handle linear units, they fail to contextualize the physical impact of wind. This tool bridges that gap by integrating the Beaufort Wind Force Scale directly into the conversion logic.

Beyond simple kinematics, wind exerts force proportional to the square of its velocity. The integrated Dynamic Pressure Calculator allows engineers and outdoor safety coordinators to estimate wind load (q) on surfaces, accounting for air density variations due to temperature and altitude. Whether calculating the fetch for wave generation or determining safe operating limits for cranes, precise data is paramount.

Formulas

The core conversion relies on the definition of the International Nautical Mile. The dynamic pressure is calculated using the Bernoulli principle approximation for incompressible flow.

Knots to m/s

v_m/s ≈ v_kt × 0.51444

Dynamic Wind Pressure

q = 12 ρ v²

Air Density (Ideal Gas)

ρ = P_atmR_specific × T

Where v is wind speed, ρ is air density (typically 1.225 kg/m³ at sea level), R_specific is the specific gas constant for dry air (287.058 J/(kg·K)), and T is absolute temperature in Kelvin.

Reference Data

Beaufort Force	Speed (Knots)	Speed (m/s)	Speed (km/h)	Description	Sea State
0	< 1	< 0.5	< 1	Calm	Sea like a mirror.
1	1-3	0.5-1.5	1-5	Light Air	Ripples with the appearance of scales are formed, but without foam crests.
2	4-6	1.6-3.3	6-11	Light Breeze	Small wavelets, still short, but more pronounced. Crests have a glassy appearance and do not break.
3	7-10	3.4-5.4	12-19	Gentle Breeze	Large wavelets. Crests begin to break. Foam of glassy appearance. Perhaps scattered white horses.
4	11-16	5.5-7.9	20-28	Moderate Breeze	Small waves, becoming longer; fairly frequent white horses.
5	17-21	8.0-10.7	29-38	Fresh Breeze	Moderate waves, taking a more pronounced long form; many white horses are formed. Chance of some spray.
6	22-27	10.8-13.8	39-49	Strong Breeze	Large waves begin to form; the white foam crests are more extensive everywhere. Probably some spray.
7	28-33	13.9-17.1	50-61	Near Gale	Sea heaps up and white foam from breaking waves begins to be blown in streaks along the direction of the wind.
8	34-40	17.2-20.7	62-74	Gale	Moderately high waves of greater length; edges of crests begin to break into spindrift. Foam is blown in well-marked streaks.
9	41-47	20.8-24.4	75-88	Strong Gale	High waves. Dense streaks of foam along the direction of the wind. Spray may affect visibility.
10	48-55	24.5-28.4	89-102	Storm	Very high waves with long overhanging crests. The resulting foam, in great patches, is blown in dense white streaks along the direction of the wind.
11	56-63	28.5-32.6	103-117	Violent Storm	Exceptionally high waves (small and medium-sized ships might be for a time lost to view behind the waves). Visibility affected.
12	≥ 64	≥ 32.7	≥ 118	Hurricane Force	The air is filled with foam and spray. Sea completely white with driving spray; visibility very seriously affected.

Frequently Asked Questions

The Beaufort scale is empirical, based on visual observations of sea state and land effects rather than instrument measurements. Historically, it allowed sailors to communicate conditions without anemometers. Our tool maps a specific input speed to the corresponding Beaufort "Force" bin, but when inputting a Beaufort number directly, we calculate the median speed of that force's range.

The tool uses the standard hydrodynamic pressure formula q = 0.5 * rho * v^2. By default, it assumes standard sea-level air density (1.225 kg/m^3). However, using the "Advanced Mode" to input local temperature and altitude significantly improves accuracy, as air density drops by approximately 3% for every 1000ft (300m) of elevation gain.

No. This tool converts sustained wind speeds. Structural engineering standards often require applying a "Gust Factor" (typically 1.5 to 2.0) to the sustained wind pressure to account for turbulence and peak loads. Always consult local building codes (e.g., ASCE 7-16) for safety-critical calculations.

A Knot is one nautical mile per hour, where a nautical mile is based on one minute of latitude (approximately 1.15 statute miles). Therefore, 1 Knot = 1.15078 MPH. Knots are the standard unit for maritime and aviation operations due to their relationship with the Earth's geometry.