Beaufort Scale Converter

Convert wind speed to the Beaufort scale

The Beaufort scale describes wind strength on a thirteen-point scale from zero, calm, to twelve, hurricane force, based on observable conditions on land and sea. This converter takes a wind speed in miles per hour, knots, kilometres per hour or metres per second and returns the Beaufort force number, its name, and a description of the conditions you would expect, such as leaves rustling or whole trees in motion. A twenty-five mile per hour wind is force five, a fresh breeze.

The scale was devised for sailors to estimate wind without instruments, and it remains a useful, intuitive way to describe wind strength.

Reading wind strength

Converting a numeric wind speed into a Beaufort force gives an immediate sense of what that wind actually does, which is more meaningful to most people than a figure in miles per hour. It is widely used in sailing, aviation and weather forecasting. The conditions descriptions help you picture the effect, from smoke rising straight up in a calm to trees being uprooted in a storm.

The converter shows the speed in several units alongside the force, so you can relate the scale to whatever unit your weather source uses. All calculation happens locally in your browser.

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