Convert Beaufort Scale to Foot per Second (Bft → ft/s)
The Beaufort scale rates wind force from 0 (calm) to 12 (hurricane), used by sailors and meteorologists.
Beaufort Scale to Foot per Second Conversion Table
10 common values| Beaufort Scale | Foot per Second |
|---|---|
| 1 Bft | 3.28084 ft/s |
| 5 Bft | 16.404199 ft/s |
| 10 Bft | 32.808399 ft/s |
| 25 Bft | 82.020997 ft/s |
| 50 Bft | 164.04199 ft/s |
| 100 Bft | 328.08399 ft/s |
| 150 Bft | 492.12598 ft/s |
| 200 Bft | 656.16798 ft/s |
| 300 Bft | 984.25197 ft/s |
| 500 Bft | 1,640.4199 ft/s |
How to Convert Beaufort Scale to Foot per Second Manually
Step by StepConverting Beaufort to feet per second is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.
- 1Take your value in BeaufortStart with the number of Beaufort (Bft) you want to convert.
- 2Multiply by 3.28084The conversion factor from Bft to ft/s is 3.28084. Multiply your value by this number.
- 3Read the result in feet per secondThe result is your value in feet per second (ft/s).
Formula
Multiply the value in Beaufort by 3.28084. For the reverse direction, multiply by 0.3048.
m/s = 0.836 × Bft^1.5Bft = (m/s ÷ 0.836)^(1/1.5)Tips
Use these in everyday conversions- Beaufort is empirical — conversion to m/s uses v = 0.836 × B^1.5.
- Force 4 (moderate breeze) = 5.5–7.9 m/s.
- Marine forecasts still use Beaufort alongside knots.
Common Mistakes
Avoid these- Treating Beaufort as a linear scale — it is a power relationship.
- Converting Beaufort to km/h by multiplying — always use the empirical formula.
- Using Beaufort for land winds — it was designed for sea conditions.
About Beaufort Scale and Foot per Second
What is the Beaufort Scale?
The Beaufort scale is an empirical wind-force scale ranging from 0 (calm) to 12 (hurricane), developed in 1805 by British Royal Navy Admiral Francis Beaufort. Originally designed for ships at sea, the scale was based on observed effects: 'How much sail can my ship safely carry?' Modern versions describe both observed effects on land and sea and corresponding wind-speed ranges. Force 0 is dead calm (under 1 km/h), Force 6 is 'strong breeze' (39–49 km/h, large branches in motion), Force 10 is a 'whole storm' (89–102 km/h), and Force 12 is hurricane (over 118 km/h). The conversion to numeric speeds follows v = 0.836 × Bft^1.5 m/s. Sailors, meteorologists, and shipping forecasts still use the Beaufort scale because its descriptive nature is intuitive: 'Force 8 gale' immediately conveys conditions to anyone familiar with the scale.
- Marine weather forecasts
- Sailing and offshore navigation
- Historical weather records
Force 5 (fresh breeze): 17–21 knots, white-caps form. Force 8 (gale): 34–40 knots. Force 12: 64+ knots.
What is the Foot per Second?
Feet per second is the standard ballistics unit for projectile speeds, American sports analytics, and engineering. Bullet velocities are universally given in fps: a .22 LR bullet flies at about 1,200 fps, a 9 mm pistol round at 1,150 fps, and a high-velocity rifle round at 3,000 fps. American football and baseball analytics increasingly use fps for measuring throwing speed, ball exit velocity, and player movement. Engineering disciplines that retain US customary units (HVAC, civil engineering) often specify air or water flow speeds in fps. The unit relates to mph (1.467 fps = 1 mph), m/s (1 fps ≈ 0.305 m/s), and the knot (1 fps ≈ 0.592 kn). Outside ballistics and US sports, m/s and km/h dominate — but in their domains, fps remains entrenched in American technical practice.
- US ballistics and firearms
- US civil-engineering flow rates
- Older US physics and engineering texts
9mm bullet muzzle velocity: ~1150 ft/s. .308 rifle: ~2700 ft/s. Free fall terminal velocity: ~195 ft/s.