Speed Unit Conversion
Quick answer: 1 m/s = 3.6 km/h ≈ 2.237 mph ≈ 1.944 kn, 1 km/h ≈ 0.2778 m/s, 1 mph = 1.609344 km/h, 1 knot = 1.852 km/h; a 10 m/s wind ≈ force 5 (fresh breeze).
m/s, km/h, mph, knots, ft/s, Mach, speed of light, the Beaufort wind scale and pace (min/km) – every speed conversion.
How the calculation works
Enter a speed and choose the unit (for example km/h or m/s). The table shows the same speed in metric and imperial units, knots and Mach, as a Beaufort force with its range and wind name, and as pace (min/km, min/mi).
Formula and assumptions
The base unit is m/s; 1 km/h = 1,000 m / 3,600 s. 1 mph = 0.44704 m/s, 1 knot = 1,852 m/h. Mach here = 340.29 m/s (standard atmosphere, 15 °C). Beaufort is non-linear: v = 0.836 · B^1.5 m/s. Pace is reciprocal: min/km = 1,000 / (60 · v).
More worked examples
- A 72 km/h wind = 20 m/s ≈ force 8 (gale) – roof wind load.
- Motorway 130 km/h ≈ 80.8 mph.
- A ship at 15 knots ≈ 27.8 km/h.
- Running at 12 km/h = a 5:00 min/km pace.
Beaufort scale
| Bft | Wind | m/s |
|---|---|---|
| 0 | calm | 0–0.2 |
| 3 | gentle breeze | 3.4–5.4 |
| 5 | fresh breeze | 8.0–10.7 |
| 7 | near gale | 13.9–17.1 |
| 9 | strong gale | 20.8–24.4 |
| 12 | hurricane force | ≥ 32.7 |
Common mistakes
- Multiplying km/h by 3.6 to get m/s instead of dividing.
- Confusing the statute mile (1,609 m) with the nautical mile (1,852 m).
- Treating Beaufort as linear – force 6 is not twice as fast as force 3.
Frequently asked questions
How many km/h is 1 m/s?
1 m/s = 3.6 km/h; to go back, divide km/h by 3.6.
What is 100 km/h in mph?
100 km/h ≈ 62.14 mph and 60 mph ≈ 96.56 km/h.
How many km/h is one knot?
1 knot = 1 nautical mile per hour = 1.852 km/h ≈ 0.514 m/s.
What wind speed is Beaufort force 6?
Force 6 (strong breeze) is 10.8–13.8 m/s, or about 39–49 km/h.
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