Convert Mile per Hour to Beaufort Scale (mph → Bft)

Converting miles per hour to Beaufort is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.

1. 1
   Take your value in miles per hour

   Start with the number of miles per hour (mph) you want to convert.
2. 2
   Multiply by 0.44704

   The conversion factor from mph to Bft is 0.44704. Multiply your value by this number.
3. 3
   Read the result in Beaufort

   The result is your value in Beaufort (Bft).

Multiply the value in miles per hour by 0.44704. For the reverse direction, multiply by 2.236936.

• ✓1 mph = 1.609 km/h = 0.447 m/s.
• ✓Quick convert: mph × 1.6 = km/h.
• ✓UK speeds posted in mph on road signs despite general metrication.

• ✗Reading a UK road sign "50" as km/h — it's mph (= 80 km/h).
• ✗Converting mph to km/h by multiplying by 1.5 instead of 1.609 — 7% error.
• ✗Assuming "mph" and "MPH" differ — capitalisation does not matter.

What is the Mile per Hour?

Miles per hour is the road-speed standard in the United States, the United Kingdom, and several Caribbean countries. American and British road signs, car speedometers, and weather reports use mph. Typical US speed limits are 25 mph (residential), 35–45 mph (urban arterials), 55–65 mph (rural highways), and 65–80 mph (interstates). The UK uses mph despite metric measurement elsewhere — a result of incomplete metrication. Mph derives from the mile (distance) and hour (time): 1 mph ≈ 1.609 km/h ≈ 0.447 m/s. World-class sprinters reach about 27 mph, professional baseball pitchers throw at 90–105 mph, and commercial airliners cruise at 550–600 mph. The unit relates to km/h (1 mph ≈ 1.609 km/h), m/s (1 mph ≈ 0.447 m/s), the knot (1 mph ≈ 0.869 kn), and ft/s (1 mph ≈ 1.467 fps).

• US and UK road speed limits
• US car speedometers
• US baseball pitch speeds

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