Wind Speed Converter — km/h to mph, Knots, Beaufort Scale

Weather forecasts, marine charts, and aviation briefings quote wind speed in different units — meters per second (m/s), kilometers per hour (km/h), miles per hour (mph), knots (kn), and sometimes the Beaufort scale. This converter translates between them from a single input.

European and many international services use km/h or m/s; US reports often use mph; aviation and shipping standardize on knots. Paste a value from a weather app or METAR and read the equivalent in any other unit. All math runs locally in your browser.

Conversions normalize through meters per second (m/s), the SI unit used by WMO and many national weather services:

km/h = m/s × 3.6  ·  mph = m/s × 2.23694  ·  knots = m/s × 1.94384

Reverse: m/s = km/h ÷ 3.6 · m/s = mph ÷ 2.23694 · m/s = knots ÷ 1.94384. One knot equals 1.852 km/h and 0.514444 m/s by definition (one nautical mile per hour).

Quick checks: 10 m/s ≈ 36 km/h ≈ 22 mph ≈ 19 knots · 50 km/h ≈ 31 mph ≈ 27 knots ≈ 14 m/s.

Beaufort force numbers describe observed sea state and wind effects — each level spans a speed band, not one exact value. Use this as a qualitative reference; the converter dropdown uses approximate midpoints.

• Bft 0 (Calm): 0 m/s · 0 km/h · 0 mph
• Bft 3 (Gentle breeze): ~4 m/s · ~14 km/h · ~9 mph · ~8 kn
• Bft 5 (Fresh breeze): ~9 m/s · ~32 km/h · ~20 mph · ~17 kn
• Bft 6 (Strong breeze): ~12 m/s · ~43 km/h · ~27 mph · ~23 kn
• Bft 8 (Gale): ~19 m/s · ~68 km/h · ~42 mph · ~37 kn
• Bft 10 (Storm): ~26 m/s · ~94 km/h · ~58 mph · ~51 kn
• Bft 12 (Hurricane): 32+ m/s · 118+ km/h · 73+ mph · 64+ kn

This page converts how fast air moves. Beaufort uses the word "force" historically (Beaufort force 0–12), but each level is defined by speed ranges and visual effects — not newtons or pounds of push.

Wind load on buildings depends on speed, air density, drag coefficient, and area — dynamic pressure scales roughly with speed squared (q ∝ v²). For force units, use the Force Converter. For vehicle speed without Beaufort, see the Speed Converter.

Weather forecasts show sustained wind and gusts in km/h, m/s, or mph depending on country — convert gusts the same way as sustained values. A 90 km/h gust equals about 56 mph and 49 knots.

Marine navigation quotes knots on GRIB files and VHF forecasts. Aviation METARs report wind in knots (e.g. 27015KT = 270° at 15 knots). Wind energy datasheets often specify cut-in and rated speeds in m/s.

50 km/h → mph: 50 ÷ 1.609344 = 31.1 mph

10 m/s → km/h: 10 × 3.6 = 36 km/h

30 knots → mph: 30 × 1.15078 = 34.5 mph

60 mph → m/s: 60 ÷ 2.23694 = 26.8 m/s — near the lower bound of Beaufort 10.

Conversions use standard exact factors. Beaufort mapping is approximate because each force spans an interval. This tool does not compute wind chill, apparent wind on a moving vessel, or terrain acceleration — only unit conversion between m/s, km/h, mph, knots, and rough Beaufort equivalents.