Beaufort Scale To mph Converter
Convert Beaufort wind force to miles-per-hour ranges for UK forecasts, walking, cycling, driving, outdoor events and marine notes.
Choose Wind Force
Wind Speed Result
Choose a Beaufort force to see the mph range.
Planning Note
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Beaufort Force In mph
The Beaufort scale describes wind by numbered force bands. In mph, Force 4 is about 13 to 18 mph, Force 6 is about 25 to 31 mph, Force 8 is about 39 to 46 mph, and Force 12 begins at about 73 mph. The force number is not a single speed; it is a range with associated effects on land or sea.
This page is written around mph because UK weather apps, road users and event planners often think in miles per hour. It also shows km/h, knots and metres per second so that a marine forecast, overseas weather source or scientific reading can be checked without opening another converter.
Conversion Method
Beaufort force maps to a standard wind speed band
mph values are rounded bands used for practical forecasts
km/h = mph x 1.609344
knots = mph x 0.868976
The converter starts with the common Beaufort-to-mph table, then calculates supporting units from the lower and upper edges of the band. Force 12 is open-ended, so the result is shown as 73 mph and above. Where midpoint is selected, the converter averages the lower and upper edges, except for Force 12 where there is no upper edge to average.
UK Planning Context
Roads And Bridges
High-sided vehicles, motorcycles and exposed bridges can be affected well before storm-force wording appears.
Walking And Cycling
Side winds, gusts and exposed hills can make a moderate wind feel much stronger.
Temporary Structures
Gazebos, banners, inflatables and market stalls need a venue-specific wind limit.
The Beaufort number is a useful way to picture wind, but a safe decision needs more context. Gusts, direction, rain, site exposure, ground conditions and the strength of equipment all matter. A sheltered garden can cope with a wind that would be a poor choice for a cliff path, harbour wall or open playing field. Check Met Office warnings, local notices and venue rules where the outcome matters.
Beaufort Scale To mph Table
| Force | Description | mph | km/h | Practical Meaning |
|---|---|---|---|---|
| 0 | Calm | 0 to 1 | 0 to 1 | Smoke rises vertically. |
| 1 | Light air | 1 to 3 | 1 to 5 | Direction shown by smoke drift. |
| 2 | Light breeze | 4 to 7 | 6 to 11 | Leaves rustle lightly. |
| 3 | Gentle breeze | 8 to 12 | 12 to 19 | Flags extend and small twigs move. |
| 4 | Moderate breeze | 13 to 18 | 20 to 28 | Loose paper and dust may lift. |
| 5 | Fresh breeze | 19 to 24 | 29 to 38 | Small trees sway. |
| 6 | Strong breeze | 25 to 31 | 39 to 49 | Large branches move. |
| 7 | Near gale | 32 to 38 | 50 to 61 | Whole trees move. |
| 8 | Gale | 39 to 46 | 62 to 74 | Twigs may break. |
| 9 | Strong gale | 47 to 54 | 75 to 88 | Minor structural damage possible. |
| 10 | Storm | 55 to 63 | 89 to 102 | Trees can be damaged. |
| 11 | Violent storm | 64 to 72 | 103 to 117 | Widespread damage possible. |
| 12 | Hurricane force | 73+ | 118+ | Severe damage possible. |
mph, Gusts And Forecast Wording
Mph is familiar, but it can hide the difference between mean wind and gusts. A forecast might show a mean wind in one range and gusts far above it. For cycling, bridge crossings, outdoor markets or boating, gusts are often the deciding factor. If a wind warning is in force, the warning text matters more than a converted Beaufort number.
Marine forecasts may still use Beaufort force because it gives a compact description of conditions. Road and event users often prefer mph. This converter is a bridge between those ways of reading wind, not a risk assessment.
Related mph Wind Conversions
| Conversion | Rule | Useful For |
|---|---|---|
| mph to km/h | multiply by 1.609344 | Metric forecasts and travel apps. |
| mph to knots | multiply by 0.868976 | Marine and aviation wind. |
| mph to m/s | multiply by 0.44704 | Engineering and weather stations. |
| knots to mph | multiply by 1.15078 | Shipping forecast to UK familiar speed. |
| km/h to mph | multiply by 0.621371 | European forecasts. |
| Force 4 to mph | 13 to 18 mph | Moderate breeze. |
| Force 6 to mph | 25 to 31 mph | Strong breeze. |
| Force 8 to mph | 39 to 46 mph | Gale. |
| Force 10 to mph | 55 to 63 mph | Storm. |
| Force 12 to mph | 73 mph and above | Hurricane-force wording. |
FAQs
How many mph is Beaufort Force 6?
Force 6 is a strong breeze, about 25 to 31 mph. It can make umbrellas hard to handle, move large branches and make exposed cycling more difficult. Gusts may be higher.
What Beaufort force is 40 mph?
Forty mph sits within Force 8, gale. If that speed is a gust rather than a mean wind, read the forecast wording carefully. For exposed sites, gale-force gusts can still be important even when the mean wind is lower.
Why is Beaufort a range instead of one speed?
The scale groups wind by observed effects and speed bands. A force number is intended to describe a band of conditions, not a single instrument reading. That is why the converter shows lower and upper limits.
Is Force 12 the same as a hurricane warning?
No. Force 12 is hurricane force on the Beaufort scale, beginning at about 73 mph. It is not the same as the official classification or warning process for tropical cyclones or UK weather warnings.
Should I use mph or knots for marine forecasts?
Marine forecasts often use knots or Beaufort force. Mph can help land users picture the speed, but sailors and harbour users should read the original marine forecast, warnings, tide and sea-state information.
Can this converter decide if a gazebo is safe?
No. It can show the wind range, but gazebo safety depends on manufacturer limits, anchoring, gusts, ground, exposure and supervision. Follow venue rules and official warnings.
Sources
- Met Office. (n.d.). Beaufort Wind Force Scale. Met Office. https://weather.metoffice.gov.uk/guides/coast-and-sea/beaufort-scale
- Royal Meteorological Society. (n.d.). The Beaufort Wind Scale. Royal Meteorological Society. https://www.rmets.org/resource/beaufort-scale
- National Weather Service. (n.d.). Beaufort Scale. National Oceanic and Atmospheric Administration. https://www.weather.gov/crp/BeaufortScale
- Bureau International des Poids et Mesures. (2019). The International System of Units (SI), 9th edition. BIPM. https://www.bipm.org/en/publications/si-brochure