Knot (unit)

Knot
Airspeed Indicator.svg
An airspeed indicator, which shows speed in knots
Unit information
Unit system
  • meteorology
  • aviation
  • maritime
Unit ofspeed
Symbolkn or kt 
Unit conversions
1 kn in ...... is equal to ...
   km/h   1.852
   mph   1.15078
   m/s   0.514444
   ft/s   1.68781

The knot (t/) is a unit of speed equal to one nautical mile per hour, exactly 1.852 km/h (approximately 1.15078 mph).[1] The ISO standard symbol for the knot is kn.[2] The same symbol is preferred by the Institute of Electrical and Electronics Engineers (IEEE); kt is also common. The knot is a non-SI unit.[3] Worldwide, the knot is used in meteorology, and in maritime and air navigation—for example, a vessel travelling at 1 knot along a meridian travels approximately one minute of geographic latitude in one hour.

Etymologically, the term derives from counting the number of knots in the line that unspooled from the reel of a chip log in a specific time.

Definitions

1 international knot =
nautical mile per hour (by definition),
1.852 kilometres per hour (exactly),[3]
0.51444 metres per second (approximately),
1.15078 miles per hour (approximately),
20.25372 inches per second (approximately)
1.68781 feet per second (approximately).

1852 m is the length of the internationally agreed nautical mile. The US adopted the international definition in 1954, having previously used the US nautical mile (1853.248 m).[4] The UK adopted the international nautical mile definition in 1970, having previously used the UK Admiralty nautical mile (6080 ft or 1853.184 m).

Conversions between common units of speed
m/s km/h mph knot ft/s
1 m/s = 1 3.6 2.236936 1.943844 3.280840
1 km/h = 0.277778 1 0.621371 0.539957 0.911344
1 mph = 0.44704 1.609344 1 0.868976 1.466667
1 knot = 0.514444 1.852 1.150779 1 1.687810
1 ft/s = 0.3048 1.09728 0.681818 0.592484 1

(Values in bold face are exact.)

Other Languages
Afrikaans: Knoop (snelheid)
العربية: عقدة (وحدة)
অসমীয়া: নট
asturianu: Nuedu (unidá)
беларуская (тарашкевіца)‎: Вузел (адзінка вымярэньня)
български: Възел (скорост)
Boarisch: Knupf (Oaheid)
བོད་ཡིག: ཚིགས།
brezhoneg: Skoulm (unanenn)
català: Nus (unitat)
čeština: Uzel (jednotka)
Ελληνικά: Κόμβος
español: Nudo (unidad)
Esperanto: Knoto
français: Nœud (unité)
Gaeilge: Muirmhíle
한국어: 노트 (단위)
हिन्दी: नॉट (इकाई)
hrvatski: Čvor
Bahasa Indonesia: Knot (satuan)
íslenska: Hnútur
Lëtzebuergesch: Knuet (Nautik)
lietuvių: Mazgas (matas)
македонски: Јазол (единица)
मराठी: नॉट (एकक)
Nederlands: Knoop (snelheid)
日本語: ノット
Nordfriisk: Knoot
norsk nynorsk: Knop
occitan: Nos (unitat)
ភាសាខ្មែរ: ណុត
Piemontèis: Neu
português: Nó (unidade)
română: Nod (unitate)
Simple English: Knot (speed)
سنڌي: ناٽ
slovenčina: Námorný uzol
slovenščina: Vozel (enota)
српски / srpski: Чвор (брзина)
srpskohrvatski / српскохрватски: Čvor (mjerna jedinica)
svenska: Knop (enhet)
ไทย: นอต
Türkçe: Knot
Tiếng Việt: Nút (đơn vị)
Winaray: Nudo
粵語: 節 (單位)
中文: 節 (單位)