💨 Beaufort Wind Scale Calculator
Enter a wind speed in any unit to get its Beaufort force number, name and the effects you'd see.
Beaufort force 5
Fresh breeze
Small trees sway
Full Beaufort scale
| Force | Description | mph |
|---|---|---|
| 0 | Calm | 0–1 |
| 1 | Light air | 1–3 |
| 2 | Light breeze | 4–7 |
| 3 | Gentle breeze | 8–12 |
| 4 | Moderate breeze | 13–18 |
| 5 | Fresh breeze | 19–24 |
| 6 | Strong breeze | 25–31 |
| 7 | Near gale | 32–38 |
| 8 | Gale | 39–46 |
| 9 | Severe gale | 47–54 |
| 10 | Storm | 55–63 |
| 11 | Violent storm | 64–72 |
| 12 | Hurricane force | 73+ |
The Beaufort scale (NWS/WMO) relates wind speed to observable effects on land and sea, from Force 0 (calm) to Force 12 (hurricane force, 73 mph / 64 knots and above). 🔒 In your browser.
How the beaufort wind scale calculator works
The Beaufort scale relates wind speed to what you can observe — smoke, leaves, branches, whole trees, structural damage. The tool converts your wind speed to miles per hour and matches it to the Beaufort force (0 to 12), giving the descriptive name and typical effects on land, based on the National Weather Service / WMO scale.
Devised by Francis Beaufort in 1805 for sailors without instruments, the scale is still used in marine and land forecasts. Force 12 (hurricane force) is open-ended, beginning at 73 mph (64 knots) with no upper limit.
Frequently asked questions
What is the Beaufort scale?
A 0–12 scale relating wind speed to observable effects, from Force 0 (calm, smoke rises straight up) to Force 12 (hurricane force, devastation). It lets you estimate wind strength without instruments.
What Beaufort force is a gale?
Force 8 is a gale (39–46 mph), when twigs break off trees and walking is difficult. Force 9 is a severe gale, and Force 10 a storm. Force 12 is hurricane force at 73 mph and above.
How do I convert wind speed to Beaufort?
Match the speed to the scale's bands: for example 19–24 mph is Force 5 (fresh breeze), 25–31 mph is Force 6 (strong breeze). Enter any speed and unit and the tool identifies the force.
What wind speed is dangerous?
Force 7 (near gale, 32+ mph) makes walking hard; Force 8–9 (gale, 39+ mph) can break branches and cause minor damage; Force 10+ (storm, 55+ mph) uproots trees and damages buildings.
Is Force 12 the top of the scale?
Yes — Force 12 (hurricane force) is the highest and is open-ended, starting at 73 mph (64 knots) with no upper bound. Extended scales to Force 17 exist for typhoons but aren't part of the standard scale.