Knots to KPH Converter
This calculator converts speed between knots and kilometres per hour, the units most commonly used at sea, in the air, and in New Zealand weather forecasts. Knots are used in shipping, aviation, and by MetService because one knot equals exactly one nautical mile per hour, and the conversion is fixed: 1 knot = 1.852 km/h. Enter a speed in knots, or enter a speed in km/h instead, and the other field updates automatically since the two are linked. You can also choose how many decimal places to display, from zero to four. Alongside the two-way conversion, it returns the equivalent speed in miles per hour, metres per second, and feet per second, with a full breakdown showing each figure and its factor. It also places your speed on the Beaufort wind scale, from Force 0 (calm) to Force 12 (hurricane), describing what that speed typically looks like, such as a fresh sailing breeze or a gale-force wind. A reference table lists common knot speeds, from light air through to commercial aircraft cruising speed, converted into km/h, mph, and m/s side by side. Use it to check wind or vessel speeds from a forecast, translate a boat's or aircraft's speed into a familiar unit, or see where a wind sits on the Beaufort scale. Because the conversion factor is an exact SI definition, every result shown is precise.
1. Knots to KPH
2. KPH to Knots (Reverse)
Enter a value in either field. The other will update automatically.
Conversion Breakdown
Context: What This Speed Looks Like
Common Speed Reference Table
| Knots | km/h | mph | m/s | Typical context |
|---|
How to Convert Knots to KPH
To convert knots to kilometres per hour, multiply the speed in knots by 1.852. This factor is exact, not approximate: one knot is defined as exactly one nautical mile per hour, and one nautical mile is defined as exactly 1,852 metres. Therefore:
km/h = knots x 1.852
To convert back from km/h to knots, divide by 1.852 (or multiply by 0.53996).
20 x 1.852 = 37.04 km/h
20 x 1.852 / 1.60934 = 23.02 mph
20 x 1.852 / 3.6 = 10.29 m/s
Why Are Speeds Measured in Knots?
Knots are used in maritime and aviation contexts because of their direct relationship to the Earth's coordinate system. One nautical mile equals one minute of arc (1/60 of a degree) of latitude. This means that if you travel one nautical mile, you have moved exactly 1/60 of a degree of latitude, making navigation calculations much simpler on a chart. A ship travelling at 10 knots for one hour covers exactly 10 nautical miles, which corresponds to a predictable angular change in latitude.
Weather services worldwide, including MetService in New Zealand, commonly report wind speeds in knots. Aviation uses knots for airspeed, ground speed, and wind speed. Maritime vessel speeds are almost universally quoted in knots.
Other Useful Conversions
| From knots to... | Multiply by | Example (1 knot) |
|---|---|---|
| Kilometres per hour (km/h) | 1.852 | 1.852 km/h |
| Miles per hour (mph) | 1.15078 | 1.151 mph |
| Metres per second (m/s) | 0.51444 | 0.514 m/s |
| Feet per second (ft/s) | 1.68781 | 1.688 ft/s |
| Feet per minute (ft/min) | 101.269 | 101.3 ft/min |
The Beaufort Wind Scale in Knots and KPH
The Beaufort scale is an empirical measure of wind speed widely used in maritime and aviation weather. It was originally devised by Admiral Francis Beaufort in 1806 and describes wind conditions from Force 0 (calm) to Force 12 (hurricane). Weather forecasts in New Zealand often use Beaufort descriptions alongside wind speeds in knots or km/h.
| Beaufort | Description | Knots | km/h |
|---|---|---|---|
| 0 | Calm | <1 | <2 |
| 1 | Light air | 1 to 3 | 2 to 6 |
| 2 | Light breeze | 4 to 6 | 7 to 11 |
| 3 | Gentle breeze | 7 to 10 | 12 to 19 |
| 4 | Moderate breeze | 11 to 16 | 20 to 30 |
| 5 | Fresh breeze | 17 to 21 | 31 to 39 |
| 6 | Strong breeze | 22 to 27 | 40 to 50 |
| 7 | Near gale | 28 to 33 | 51 to 62 |
| 8 | Gale | 34 to 40 | 63 to 74 |
| 9 | Strong gale | 41 to 47 | 75 to 88 |
| 10 | Storm | 48 to 55 | 89 to 102 |
| 11 | Violent storm | 56 to 63 | 103 to 117 |
| 12 | Hurricane | 64+ | 119+ |
Related Calculators
- Essential Calculators: the full collection of converters and tools.
- Speed Converter: convert between km/h, mph, m/s, and more.
- KM to Miles Converter: convert kilometres to miles.
- Crosswind Calculator: calculate crosswind and headwind components from wind speed and direction.
- Speed Calculator: calculate speed, distance, or time from the other two values.
Sources and method: The conversion factor 1 knot = 1.852 km/h is exact under the International System of Units (SI) as published by the Bureau International des Poids et Mesures (BIPM). One nautical mile = 1,852 metres exactly, as defined by the International Hydrographic Organization. The Beaufort scale descriptions and speed ranges follow the World Meteorological Organization (WMO) specification.