Knots, Nautical Miles and Beaufort Scale Converter
Value to convert
Conversion result
Enter a value and select its unit to see the conversion.
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How to use the converter
- Choose Wind speed and Beaufort or Nautical distance.
- Enter a value and select the unit it is currently expressed in.
- Select Convert. A speed produces exact unit equivalents and a Beaufort classification; a Beaufort force produces published speed ranges.
- Copy or download the result if you need a plain-text record.
Knot versus nautical mile
A nautical mile (nmi) is distance. A knot (kn) is speed: one nautical mile per hour. Writing “knots per hour” for ordinary speed is incorrect because the time component is already built into the knot.
1 kn = exactly 1.852 km/h
1 kn ≈ 1.15078 mph
1 kn ≈ 0.514444 m/s
Beaufort wind force reference
The table follows the Met Office marine scale. Wind bands are shown in whole knots; Force 12 is hurricane force, which describes wind strength and does not by itself mean a tropical cyclone.
| Force | Term | Wind | Open-sea description |
|---|---|---|---|
| 0 | Calm | <1 kn | Calm, glassy |
| 1 | Light air | 1–3 kn | Calm, rippled |
| 2 | Light breeze | 4–6 kn | Smooth, wavelets |
| 3 | Gentle breeze | 7–10 kn | Slight |
| 4 | Moderate breeze | 11–16 kn | Slight to moderate |
| 5 | Fresh breeze | 17–21 kn | Moderate |
| 6 | Strong breeze | 22–27 kn | Rough |
| 7 | Near gale | 28–33 kn | Rough to very rough |
| 8 | Gale | 34–40 kn | Very rough to high |
| 9 | Strong gale | 41–47 kn | High |
| 10 | Storm | 48–55 kn | Very high |
| 11 | Violent storm | 56–63 kn | Very high |
| 12 | Hurricane force | 64+ kn | Phenomenal |
Published sea descriptions refer to well-developed wind waves in the open sea. The sea can lag behind a rising wind, and enclosed or sheltered water may look different.
Frequently asked questions
Is a knot the same as a nautical mile?
No. A nautical mile measures distance; a knot measures speed. One knot means one nautical mile traveled per hour.
How many kilometers per hour is one knot?
Exactly 1.852 km/h. This follows from the international nautical mile being exactly 1,852 meters.
How many statute miles are in one nautical mile?
Approximately 1.15078 statute miles. Conversely, one statute mile is approximately 0.868976 nautical miles.
Can Beaufort force be converted to one exact speed?
No. Beaufort forces are wind-speed bands. When you enter a Beaufort force, this tool reports its published range and a representative mean where the Met Office table provides one.
Does the Beaufort result describe gusts?
No. The Beaufort classification here is for mean wind speed. Short-lived gusts can be stronger and should be checked in an official marine forecast.
Why might the observed sea state not match the Beaufort description?
Wave development depends on how long and how far the wind has blown, plus water depth, currents, shelter and nearby land. The Beaufort sea descriptions assume well-developed waves in the open sea.
Does this replace a marine forecast?
No. It only converts units and classifies an entered mean wind speed. Check current official forecasts, warnings and local conditions before making decisions.
Are my values uploaded or tracked?
No. Conversions run locally in your browser, and entered values are not sent, stored or attached to analytics events.
Method and limits
- Speed conversions use the exact international nautical mile and exact SI/statute conversion factors.
- Numeric wind speeds are assigned to the Met Office whole-knot bands at 1, 4, 7, 11, 17, 22, 28, 34, 41, 48, 56 and 64 knots.
- Beaufort force is ordinal, not a linear unit. A change of one force does not represent one fixed increase in speed.
- Force 12 has no finite upper bound or representative mean in the cited table, so the tool reports an open-ended range.
Safety disclaimer: This educational converter is not weather routing, navigation advice or a substitute for official marine forecasts, warnings, vessel limits and seamanship.
Sources
Last reviewed: August 2, 2026.