Wind Speed Converter: Convert mph, km/h, Knots and m/s
Read the wind, not only the unit: Convert wind speed between mph, km/h, knots, m/s and ft/s instantly, with a full conversion chart and the Beaufort wind scale.
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What this wind speed means on land
Beaufort force4
DescriptionModerate breeze
Dust and loose paper lift.
This interpretation uses sustained wind. A brief gust can be much stronger than the value entered.
Beaufort wind scale
| Force | Name | Wind speed | Effects on land |
|---|---|---|---|
| 0 | Calm | < 1 mph | Smoke rises vertically |
| 1 | Light air | 1-3 mph | Smoke drifts, vanes still |
| 2 | Light breeze | 4-7 mph | Leaves rustle, wind felt on face |
| 3 | Gentle breeze | 8-12 mph | Leaves and small twigs in motion |
| 4 | Moderate breeze | 13-18 mph | Dust and loose paper lift |
| 5 | Fresh breeze | 19-24 mph | Small trees sway |
| 6 | Strong breeze | 25-31 mph | Large branches move, umbrellas struggle |
| 7 | Near gale | 32-38 mph | Whole trees in motion |
| 8 | Gale | 39-46 mph | Twigs break off, walking is hard |
| 9 | Strong gale | 47-54 mph | Minor structural damage |
| 10 | Storm | 55-63 mph | Trees uprooted, considerable damage |
| 11 | Violent storm | 64-72 mph | Widespread damage |
| 12 | Hurricane force | 73+ mph | Devastation; hurricane categories begin |
Why wind units differ across forecasts, sailing and aviation
Enter a wind speed in any field and the others update instantly. Forecasts in the US use mph, most of the world uses km/h, sailors and aviators use knots, and scientists use meters per second - this tool speaks all of them.
For the evidence, limits and practical use behind this result, read Wind Chill Explained. The weather tools guide explains when each calculator is the right one.
1 mph = 1.609 km/h1 knot = 1.151 mph1 m/s = 2.237 mph
Reading wind in the real world
- Quick mental math: knots to mph, add half again minus a bit (20 kn ≈ 23 mph); mph to km/h, multiply by 1.6.
- Gusts vs. sustained wind: forecasts quote sustained wind; gusts typically run 30-40% higher.
- Anchor the scale: 10 mph moves leaves, 30 mph moves whole trees, 60 mph moves roof shingles.
Wind speed conversion chart
| mph | km/h | kn | m/s | ft/s |
|---|---|---|---|---|
| 1 | 1.61 | 0.87 | 0.45 | 1.47 |
| 5 | 8.05 | 4.34 | 2.24 | 7.33 |
| 10 | 16.09 | 8.69 | 4.47 | 14.67 |
| 15 | 24.14 | 13.03 | 6.71 | 22 |
| 20 | 32.19 | 17.38 | 8.94 | 29.33 |
| 25 | 40.23 | 21.72 | 11.18 | 36.67 |
| 30 | 48.28 | 26.07 | 13.41 | 44 |
| 40 | 64.37 | 34.76 | 17.88 | 58.67 |
| 50 | 80.47 | 43.45 | 22.35 | 73.33 |
| 60 | 96.56 | 52.14 | 26.82 | 88 |
| 74 | 119.09 | 64.3 | 33.08 | 108.53 |
| 100 | 160.93 | 86.9 | 44.7 | 146.67 |
| 150 | 241.4 | 130.35 | 67.06 | 220 |
Wind-speed decisions and unit questions
How fast is a knot compared to mph?
One knot is one nautical mile per hour, which equals 1.151 mph or 1.852 km/h. A 20-knot wind is about 23 mph.
What wind speed is dangerous?
Sustained winds around 40 mph (64 km/h) make walking difficult and break twigs; 58+ mph (93 km/h) triggers severe-thunderstorm warnings in the US; hurricane force starts at 74 mph (119 km/h).
Why do meteorologists use knots?
Weather observations follow marine and aviation conventions, where distances are in nautical miles. Public forecasts translate to mph or km/h.