Wind Speed Calculator — Convert Wind Speed Units
Convert wind speed between m/s, km/h, mph, knots, and ft/s. Includes Beaufort scale classification with sea and land conditions. Essential for meteorology, sailing, aviation, and outdoor activities. See also our Speed Converter and Weather Calculators.
Enter wind speed value and select unit to convert.
Beaufort Wind Scale
| Force | Knots | Description | Sea Condition | Land Condition |
|---|---|---|---|---|
| 0 | < 1 | Calm | Sea like a mirror | Calm. Smoke rises vertically. |
| 1 | 1-3 | Light Air | Ripples with appearance of scales, no foam crests | Wind motion visible in smoke. |
| 2 | 4-6 | Light Breeze | Small wavelets, crests have glassy appearance | Wind felt on exposed skin. Leaves rustle. |
| 3 | 7-10 | Gentle Breeze | Large wavelets, crests begin to break | Leaves and smaller twigs in constant motion. |
| 4 | 11-15 | Moderate Breeze | Small waves, fairly frequent white horses | Dust and loose paper raised. Small branches move. |
| 5 | 16-21 | Fresh Breeze | Moderate waves, many white horses, some spray | Branches of moderate size move. Small trees sway. |
| 6 | 22-27 | Strong Breeze | Large waves, white foam crests extensive | Large branches in motion. Umbrella use difficult. |
| 7 | 28-33 | Near Gale | Sea heaps up, foam blown in streaks | Whole trees in motion. Effort to walk against wind. |
| 8 | 34-40 | Gale | Moderately high waves, crests break into spindrift | Twigs broken from trees. Cars veer on road. |
| 9 | 41-47 | Severe Gale | High waves, dense foam streaks, spray affects visibility | Larger branches break off trees. |
| 10 | 48-55 | Storm | Very high waves, sea surface white with foam | Trees uprooted. Structural damage occurs. |
| 11 | 56-63 | Violent Storm | Exceptionally high waves, visibility affected | Widespread vegetation and structural damage. |
| 12 | 64+ | Hurricane | Air filled with foam and spray, visibility severely affected | Considerable and widespread damage. |
How to Convert Wind Speed
- Enter the wind speed value in the input field.
- Select the unit (km/h, mph, m/s, knots, or ft/s).
- Click Calculate to see all conversions and Beaufort classification.
- Refer to the Beaufort scale table for sea and land conditions.
Wind Speed Conversion Formula
Wind Speed Conversions (base = m/s):
1 m/s = 3.6 km/h = 2.237 mph = 1.944 knots = 3.281 ft/s
1 km/h = 0.2778 m/s = 0.6214 mph = 0.5400 knots
1 mph = 0.4470 m/s = 1.609 km/h = 0.8690 knots
1 knot = 0.5144 m/s = 1.852 km/h = 1.151 mph
1 ft/s = 0.3048 m/s = 1.097 km/h = 0.6818 mph
Beaufort Scale Formula (approximate):
v = 0.836 × B^(3/2) m/s
Where B = Beaufort number (0-12)Example Conversion
Problem: Convert 50 km/h wind to other units.
Solution:
• m/s: 50 ÷ 3.6 = 13.89 m/s
• mph: 50 × 0.6214 = 31.07 mph
• knots: 50 × 0.5400 = 27.00 knots
• Beaufort: Force 6 (Strong Breeze)
Answer: 50 km/h = 13.89 m/s = 31.07 mph = 27.00 knots = Beaufort 6
Technical Details
Wind speed is measured using anemometers — rotating cup anemometers for surface stations and sonic anemometers for research. Meteorological wind speed is typically reported as a 10-minute average at 10 meters height (WMO standard). In the US, a 2-minute average is used. Wind gusts are the maximum 3-second wind speed recorded during the observation period.
The Beaufort scale was devised in 1805 by Sir Francis Beaufort of the Royal Navy as a way to standardize wind observations at sea. It was originally based on the amount of sail a warship could carry. The modern scale relates wind speed to observed sea state and land effects, ranging from Force 0 (calm, less than 1 knot) to Force 12 (hurricane, 64+ knots). It remains the standard for marine weather forecasts worldwide.
Frequently Asked Questions
What is the Beaufort scale?
The Beaufort scale is an empirical measure relating wind speed to observed conditions at sea and on land. It ranges from 0 (calm) to 12 (hurricane force). Created by Sir Francis Beaufort in 1805.
What wind speed is dangerous?
Winds above Beaufort 8 (39+ mph / 63+ km/h) are considered gale force and dangerous. Hurricane force starts at Beaufort 12 (73+ mph / 118+ km/h). Most outdoor activities become unsafe above Beaufort 6.
Why do sailors use knots?
Knots (nautical miles per hour) are used in maritime and aviation because they relate directly to latitude — 1 nautical mile = 1 minute of latitude. This makes navigation calculations simpler on charts.
How do I convert knots to km/h?
Multiply knots by 1.852 to get km/h. For example, 20 knots × 1.852 = 37.04 km/h. Conversely, divide km/h by 1.852 to get knots.
What is the difference between wind speed and wind gust?
Wind speed is the sustained average over a period (usually 2-10 minutes). Wind gusts are brief increases lasting 3-5 seconds. Gusts can be 30-50% higher than sustained speed.
Objective of Measurement:
Measurement is the most important aspect of our life. We use measurement in science, engineering, business trading, personal life, education, and more other fields. As technology is growing day by day so we need a highly accurate and easy convenient global measuring system in each and every field. It is essential to use standard measurement in every field that everyone to be sure that they not get cheated.
History of Measurement:
In history for measurement people used the human body as a tool. For measuring length used forearm, hand, foot & finger as a unit. The foot, finger is a subdivided shorter unit of a length. This type of measurement is not accurate cause different in size of the arm & finger for different people & some of the countries still using it. In history, there were lots of measuring systems developed but mostly used imperial, the metric system of measurement. We use these systems for measure distances, volume, weight, speed, area etc. Due to this a major problem everyone is facing while doing trading between the countries. A huge improvement in civilization, It necessary to improve measuring standards. Nowadays International Standard (SI) units are used as a global measurement system.