UnitConvConvert
Bft
Speednavigationmarinescientific

What is a beaufort scale?

Empirical wind-force scale from 0 (calm) to 12 (hurricane)

Definition

The Beaufort scale is an empirical wind-force scale from 0 (calm) to 12 (hurricane). Created by Francis Beaufort in 1805, it correlates wind force with observed effects on sea or land. Force 8 (34–40 knots) is a gale; force 12 is above 64 knots.

Common uses

  • Marine weather forecasts
  • Sailing and offshore navigation
  • Historical weather records

🌍 Real-world scale

Force 5 (fresh breeze): 17–21 knots, white-caps form. Force 8 (gale): 34–40 knots. Force 12: 64+ knots.

Convert from Beaufort

9 conversions
Beaufort Scale to Kilometer per Hour1 Bft = 3.6 km/hBeaufort Scale to Meter per Second1 Bft = 1 m/sBeaufort Scale to Mile per Hour1 Bft = 2.23694 mphBeaufort Scale to Knot1 Bft = 1.94384 knBeaufort Scale to Mach1 Bft = 0.002939 MaBeaufort Scale to Foot per Second1 Bft = 3.28084 ft/sBeaufort Scale to Centimeter per Second1 Bft = 100 cm/sBeaufort Scale to Yard per Minute1 Bft = 65.6168 yd/minBeaufort Scale to Inch per Minute1 Bft = 2,364.07 in/min

Convert to Beaufort

9 conversions
Kilometer per Hour to Beaufort Scale1 km/h = 0.2778 BftMeter per Second to Beaufort Scale1 m/s = 1 BftMile per Hour to Beaufort Scale1 mph = 0.447 BftKnot to Beaufort Scale1 kn = 0.5144 BftMach to Beaufort Scale1 Ma = 340.29 BftFoot per Second to Beaufort Scale1 ft/s = 0.3048 BftCentimeter per Second to Beaufort Scale1 cm/s = 0.01 BftYard per Minute to Beaufort Scale1 yd/min = 0.01524 BftInch per Minute to Beaufort Scale1 in/min = 0.000423 Bft

Tips

  • 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

  • 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.

FAQ about the beaufort scale

What is a beaufort scale?
The Beaufort scale is an empirical wind-force scale from 0 (calm) to 12 (hurricane). Created by Francis Beaufort in 1805, it correlates wind force with observed effects on sea or land. Force 8 (34–40 knots) is a gale; force 12 is above 64 knots.
Where is the beaufort scale used?
The beaufort scale is commonly used for: Marine weather forecasts; Sailing and offshore navigation; Historical weather records.
What is an example of a beaufort scale in real life?
Force 5 (fresh breeze): 17–21 knots, white-caps form. Force 8 (gale): 34–40 knots. Force 12: 64+ knots.
What category does the beaufort scale belong to?
The beaufort scale is a unit of speed, part of the 10-unit speed category on UnitConv.
How accurate are beaufort scale conversions?
All conversion factors follow NIST and BIPM international standards to 8 significant figures — the highest practical accuracy.
Explore all 10 speed units and their conversions.🚀 Speed hub →