Aviation speed conversions
Aviation commonly uses knots for airspeed and groundspeed, but manuals, weather products, road-based references and international material may use miles per hour, kilometers per hour or meters per second. Converting correctly matters because a small unit mistake can produce a large planning error.
Knots and nautical miles
One knot means one nautical mile per hour. A nautical mile is based on Earth geometry and is about 1.1508 statute miles or 1.852 kilometers. That direct relationship is why knots pair naturally with aviation distance and time calculations.
Knots to mph
Multiply knots by about 1.1508 to get statute miles per hour. For example, 100 knots is about 115.1 mph. To convert mph back to knots, divide by 1.1508.
Knots to km/h
Multiply knots by 1.852. A speed of 120 knots is about 222 km/h. Divide km/h by 1.852 to return to knots.
Meters per second
One knot is about 0.5144 meters per second. This unit appears in engineering and some meteorological material. Wind forecasts or technical references may use m/s even when cockpit products use knots.
Do not confuse IAS, TAS and groundspeed
A unit conversion changes only the unit. It does not turn indicated airspeed into true airspeed or true airspeed into groundspeed. Those are different physical quantities. Convert the correct speed quantity rather than assuming every number labeled “speed” is interchangeable.
Use a reasonableness check
Because mph is numerically larger than knots for the same speed, 100 knots becoming 87 mph would be an obvious sign that the conversion direction was reversed.
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