Wind Speed Converter
Convert between mph, km/h, knots, m/s, and ft/s instantly. See wind speeds on the Beaufort scale with descriptions of conditions at sea and on land.
Type a speed into any box. The other units update as you type.
Large waves, white foam crests
Large branches in motion, umbrellas difficult
Wind Speed Conversion Chart
Common speeds in mph with their knots, km/h, and m/s equivalents. 39 mph is where a tropical storm begins and 74 mph is hurricane force.
| mph | knots | km/h | m/s |
|---|---|---|---|
| 5 | 4.3 | 8.0 | 2.2 |
| 10 | 8.7 | 16.1 | 4.5 |
| 15 | 13.0 | 24.1 | 6.7 |
| 20 | 17.4 | 32.2 | 8.9 |
| 25 | 21.7 | 40.2 | 11.2 |
| 30 | 26.1 | 48.3 | 13.4 |
| 35 | 30.4 | 56.3 | 15.6 |
| 39 | 33.9 | 62.8 | 17.4 |
| 40 | 34.8 | 64.4 | 17.9 |
| 45 | 39.1 | 72.4 | 20.1 |
| 50 | 43.4 | 80.5 | 22.4 |
| 60 | 52.1 | 96.6 | 26.8 |
| 74 | 64.3 | 119.1 | 33.1 |
| 100 | 86.9 | 160.9 | 44.7 |
Quick rules: 1 knot = 1.151 mph = 1.852 km/h, and 1 m/s = 2.237 mph = 3.6 km/h. To get mph from km/h, multiply by 0.621.
Common Wind Speed References
Beaufort Wind Scale
| Force | Description | mph | knots | km/h | m/s |
|---|---|---|---|---|---|
| 0 | Calm | < 1 | < 1 | < 2 | < 0.5 |
| 1 | Light Air | 1-3 | 1-3 | 2-5 | 0.5-1.5 |
| 2 | Light Breeze | 4-7 | 4-6 | 6-11 | 1.6-3.3 |
| 3 | Gentle Breeze | 8-12 | 7-10 | 12-19 | 3.4-5.4 |
| 4 | Moderate Breeze | 13-18 | 11-16 | 20-28 | 5.5-7.9 |
| 5 | Fresh Breeze | 19-24 | 17-21 | 29-38 | 8.0-10.7 |
| 6 | Strong Breeze | 25-31 | 22-27 | 39-49 | 10.8-13.8 |
| 7 | Near Gale | 32-38 | 28-33 | 50-61 | 13.9-17.1 |
| 8 | Gale | 39-46 | 34-40 | 62-74 | 17.2-20.7 |
| 9 | Strong Gale | 47-54 | 41-47 | 75-88 | 20.8-24.4 |
| 10 | Storm | 55-63 | 48-55 | 89-102 | 24.5-28.4 |
| 11 | Violent Storm | 64-72 | 56-63 | 103-117 | 28.5-32.6 |
| 12 | Hurricane | 73+ | 64+ | 118+ | 32.7+ |
Understanding Wind Speed Units
Knots
The standard unit for aviation and maritime use. One knot equals one nautical mile per hour, which is about 1.15 mph or 1.85 km/h.
Meters per Second
The SI unit for speed, used in scientific contexts and weather services in many countries. Easy to convert to km/h (multiply by 3.6).
Miles per Hour
Common in the US and UK for weather reports. Hurricane categories are often described in mph (Cat 1 starts at 74 mph).
Track Wind in WeatherAI
WeatherAI shows wind speed in your preferred unit, with gusts, wind direction, and animated wind maps for any location.
Free to download • No credit card required
More Wind Resources
Wind calculators and explainers for storms, runways, and cold-weather exposure.
Tool
Crosswind Calculator
Calculate headwind and crosswind components for any runway and wind combination.
Guide
Hurricane Categories Explained
Understand what each Saffir-Simpson category says and what it does not say about a storm's risk.
Guide
What Is a Derecho?
Learn how these long-lived windstorms differ from tornadoes and hurricanes, and why they are so destructive.
Tool
Wind Chill Calculator
Estimate cold-weather exposure risk from temperature and wind speed.
Tool
Temperature Converter
Convert between Fahrenheit, Celsius, and Kelvin instantly.