Knot (kt)

Definition

A knot is the standard unit of speed used in aviation and maritime operations. One knot equals one nautical mile per hour, or precisely 1.852 kilometers per hour (km/h) or 1.1508 miles per hour (mph).

The abbreviation is kt (plural: kt or kts, depending on regional usage), and it is used in aircraft performance, wind reporting, and navigation.

Why Use Knots in Aviation?

Matches the nautical mile, which is based on Earth's latitude/longitude grid
Simplifies navigation over charts, which are based on geographic coordinates
Used globally in aircraft manuals, ATIS/METAR, ATC phraseology, and instruments

Conversion Table

Speed	In Knots	In km/h	In mph
1 kt	1	1.852	1.151
50 kt	50	92.6	57.5
100 kt	100	185.2	115.1
250 kt	250	463	288
500 kt	500	926	575

Where Knots Are Used

Application	Example
Aircraft speed	“Cruising at 120 kt”
Wind reports	“Wind 260 degrees at 18 kt”
Minimum/maximum approach speeds	“Final approach speed is 65 kt”
Speed limits in airspace	“Maximum 250 kt below FL100”

Knots are used in both Indicated Airspeed (IAS) and True Airspeed (TAS) values, as well as for groundspeed (GS), depending on context.

Phraseology Examples

“Wind 270 degrees, 15 knots”
“Reduce speed to 180 knots”
“Final approach speed is 75 knots, landing runway 09”

Knots vs. Other Units

Aviation uses knots and nautical miles to maintain consistency with charts, navigation systems, and procedures
Speeds in kilometers per hour or miles per hour are not used in standard aviation contexts
Aircraft manuals, GPS devices, and ATIS broadcasts universally refer to knots

Tips for Pilots

✅ Know your aircraft’s key speeds in knots (e.g., Vx, Vy, Vr, Vref)
✅ Monitor wind components in knots for takeoff and landing calculations
✅ Use LearnATC to practice wind and speed reporting in phraseology exercises

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