Wind Speed to Beaufort Scale – Force 0 to 12 Explained
The Beaufort scale is a classic way to describe wind strength using numbers from 0 (calm) to 12 (hurricane force). Each level combines a range of wind speeds with descriptive terms and typical effects on the sea and on land. This Wind Speed to Beaufort Scale Calculator helps you translate a measured or forecast wind speed into a Beaufort force number and interpret what that means in practical terms.
Enter a wind speed in your preferred unit – meters per second, kilometers per hour, miles per hour, knots, or feet per second – and the calculator converts it internally to meters per second, finds the correct Beaufort level and displays the standard description and effects.
How the Beaufort Scale Works
The Beaufort scale originated in the early 19th century as a way for sailors to describe wind strength based on observations of the sea surface and sail behavior. Modern versions of the scale associate each Beaufort number with a range of wind speeds and more detailed descriptions for both sea and land.
- Beaufort 0: Calm, smoke rises vertically, sea like a mirror.
- Beaufort 3: Gentle breeze, flags extended, small wavelets at sea.
- Beaufort 6: Strong breeze, large waves, difficult to use umbrellas on land.
- Beaufort 9: Strong gale, high waves, slight structural damage possible on land.
- Beaufort 12: Hurricane force, very high waves and widespread damage.
Weather services, mariners and outdoor enthusiasts still use the Beaufort scale as a convenient shorthand for describing wind conditions and their impact.
Standard Beaufort Wind Speed Ranges
While there are minor variations between references, a commonly used set of thresholds in meters per second is:
- 0: 0.0–0.2 m/s – Calm
- 1: 0.3–1.5 m/s – Light air
- 2: 1.6–3.3 m/s – Light breeze
- 3: 3.4–5.4 m/s – Gentle breeze
- 4: 5.5–7.9 m/s – Moderate breeze
- 5: 8.0–10.7 m/s – Fresh breeze
- 6: 10.8–13.8 m/s – Strong breeze
- 7: 13.9–17.1 m/s – Near gale
- 8: 17.2–20.7 m/s – Gale
- 9: 20.8–24.4 m/s – Strong gale
- 10: 24.5–28.4 m/s – Storm
- 11: 28.5–32.6 m/s – Violent storm
- 12: ≥ 32.7 m/s – Hurricane force
The calculator uses these ranges to determine the Beaufort force for your input speed and then shows the matching description and sea/land effects.
Sea and Land Effects on the Beaufort Scale
Each Beaufort level is defined not only by wind speed but also by what you would see in the environment. Typical examples include:
- At sea: From small ripples and wavelets at low forces to high waves, foam streaks and spray at higher levels.
- On land: From still smoke and barely moving leaves at low forces to broken tree branches, difficulty walking and structural damage at high forces.
The calculator’s result cards show concise sea and land descriptions for the Beaufort level that matches your wind speed, helping you visualize conditions beyond just a number.
Why Use a Beaufort Calculator Instead of Just Wind Speed?
Wind speed alone is precise, but it can be hard to interpret without context. A Beaufort number:
- Groups similar conditions into simple categories.
- Makes it easy to communicate strength to non-technical audiences.
- Connects a speed to real-world effects you can feel and see.
- Helps compare conditions across different forecasts and locations.
How to Use the Wind Speed to Beaufort Scale Calculator
- Choose the unit that matches your forecast or measurement (mph, km/h, m/s, knots or ft/s).
- Enter the wind speed value and select how many decimal places you want in the results.
- Click Convert to Beaufort Force to see the Beaufort number, description and effects.
- Toggle the option to show equivalent wind speeds in all units if you want a quick conversion table.
- Open the Full Beaufort Scale Table tab for a complete reference from 0 to 12.
Remember that local terrain, obstacles and measurement height can influence the wind you actually feel. The Beaufort scale is a standardized reference, not a substitute for direct local observations.
Related Weather and Outdoor Planning Tools
Use these additional tools from MyTimeCalculator when planning outdoor activities and safety:
Beaufort Scale FAQs
Frequently Asked Questions About the Beaufort Scale
Understand how Beaufort force levels relate to real-world wind conditions.
The original Beaufort scale was based on visual observations rather than a specific unit system. Modern versions are usually defined in meters per second or knots, but they can be converted to and from mph and km/h. This calculator handles those conversions automatically for you.
Over time, various meteorological organizations have published slightly different threshold values and rounding conventions. The differences are usually small. This calculator uses a widely accepted modern set of thresholds that matches most practical references.
Beaufort levels are associated with typical sea states and qualitative wave descriptions, but they do not guarantee a specific wave height because swell, fetch and water depth also matter. Use Beaufort as a rough guide and refer to detailed marine forecasts for wave height information.