Wind Speed Calculator
Instantly convert wind speed between knots, mph, km/h, and m/s. Perfect for sailors, pilots, meteorologists, and outdoor enthusiasts.
Convert Wind Velocity
Enter your wind speed value and select the unit below to instantly see the equivalent measurements across all major systems, along with the corresponding Beaufort scale classification.
Wind Speed Converter
Get instant conversions and Beaufort scale context.
Understanding Wind Speed
Key concepts for accurate measurement and safety
The Beaufort Scale
Developed in 1805, this scale relates wind speed to observable conditions at sea or on land, ranging from Force 0 (Calm) to Force 12 (Hurricane).
Measurement Tools
Wind speed is measured using an anemometer. Traditional models use rotating cups, while modern meteorological stations often use ultrasonic sensors.
Gusts vs. Sustained Wind
Meteorological reports typically cite "sustained" wind speed (averaged over 10 minutes). "Gusts" are brief, sudden increases in speed, often 1.5x the sustained rate.
Safety Thresholds
For recreational activities, winds above 20 knots (Force 5) require caution for small boats, and winds above 30 knots (Force 7) are generally considered hazardous for small craft.
The Beaufort Wind Scale
A standardised empirical measure that relates wind speed to observed conditions at sea and on land.
| Force | Description | Speed (Knots) | Speed (mph) | Land Conditions |
|---|---|---|---|---|
| Calm | < 1 | < 1 | Smoke rises vertically | |
| Light Air | 1 – 3 | 1 – 3 | Direction shown by smoke drift | |
| Light Breeze | 4 – 6 | 4 – 7 | Wind felt on face, leaves rustle | |
| Gentle Breeze | 7 – 10 | 8 – 12 | Leaves and small twigs in constant motion | |
| Moderate Breeze | 11 – 16 | 13 – 18 | Raises dust and loose paper, small branches move | |
| Fresh Breeze | 17 – 21 | 19 – 24 | Small trees in leaf begin to sway | |
| Strong Breeze | 22 – 27 | 25 – 31 | Large branches in motion, whistling in wires | |
| Near Gale | 28 – 33 | 32 – 38 | Whole trees in motion, inconvenience in walking | |
| Gale | 34 – 40 | 39 – 46 | Twigs break off trees, generally impedes progress | |
| Strong Gale | 41 – 47 | 47 – 54 | Slight structural damage (chimney pots, slates) | |
| Storm | 48 – 55 | 55 – 63 | Seldom experienced inland; trees uprooted | |
| Violent Storm | 56 – 63 | 64 – 72 | Very rarely experienced; accompanied by widespread damage | |
| Hurricane | ≥ 64 | ≥ 73 | Devastating damage, air filled with debris |
Wind Speed FAQ
Answers to the most frequently asked questions about wind measurement, conversions, and safety.
To convert knots to mph, multiply the wind speed in knots by 1.15078. For example, 10 knots is approximately 11.5 mph. This calculator handles the conversion automatically.
The Beaufort scale is an empirical measure that relates wind speed to observed conditions at sea or on land. It ranges from Force 0 (Calm, <1 knot) to Force 12 (Hurricane, ≥64 knots), providing a standardised way to describe wind intensity without instruments.
Most consumer drones are rated for maximum wind resistance of around 10–12 m/s (22–27 mph, or Force 4–5 on the Beaufort scale). For safe, stable, and cinematic flight, it is highly recommended to fly in winds below 8 m/s (18 mph).
Wind speed is traditionally measured using an anemometer, which uses rotating cups or propellers to calculate velocity. Modern meteorological stations may also use ultrasonic sensors or Doppler radar for highly accurate, maintenance-free readings.
A knot is one nautical mile per hour. A nautical mile is based on the Earth's circumference and is exactly 1.852 kilometres (or about 1.15078 statute miles). Therefore, a knot is slightly faster than a standard mile per hour.