What is the Beaufort scale?

The Beaufort scale is a standardized way to describe wind strength using 13 levels from 0 (calm) to 12 (hurricane). Each level corresponds to a wind speed range and observable effects on land and sea.

How do I convert wind speed to Beaufort?

Enter the speed and choose the unit (knots, km/h, m/s, mph). The speed is compared to the official Beaufort ranges to output the corresponding force number (0–12) and description.

Why do sources show slightly different ranges?

Different meteorological services sometimes round knots and km/h differently. This tool uses commonly accepted ranges similar to WMO/UK Met Office tables.

Beaufort Scale Converter – wind speed to Beaufort number

Beaufort Scale Converter

Convert your measured wind speed into the classical Beaufort number (0–12) and see the description (calm, gentle breeze, storm…). Supports knots, km/h, m/s and mph, and also converts back from Beaufort to typical speed ranges.

Wind speed value

Unit

OR pick Beaufort

Converted 10 km/h → Beaufort 2 (light breeze)

Beaufort number

Description

Calm

Typical range

0 – 1 km/h

Beaufort scale (0–12)

Force	Name	m/s	km/h	knots	Sea / Land effects (short)

How conversion works

The Beaufort scale is defined by ranges. For example, 6–11 km/h → Beaufort 2. So to convert, we:

Normalize your input to m/s.
Find the scale entry whose range contains that m/s value.
Return the number, name, and typical range in your original unit.

Example: 10 km/h

10 km/h ÷ 3.6 = 2.78 m/s, which is in the range 1.6–3.3 m/s → Beaufort 2.

Standard ranges used

We follow common international tables (WMO, Met Office, national met services). Minor rounding may occur between knots and km/h, but the Beaufort number stays the same.